diff --git a/samcli/cli/cli_config_file.py b/samcli/cli/cli_config_file.py
index e4606e4555..bfc295c01b 100644
--- a/samcli/cli/cli_config_file.py
+++ b/samcli/cli/cli_config_file.py
@@ -10,49 +10,67 @@
 import logging
 import os
 from pathlib import Path
+from typing import Any, Callable, Dict, List, Optional
 
 import click
+from click.core import ParameterSource
 
 from samcli.cli.context import get_cmd_names
 from samcli.commands.exceptions import ConfigException
 from samcli.lib.config.samconfig import DEFAULT_CONFIG_FILE_NAME, DEFAULT_ENV, SamConfig
 
-__all__ = ("TomlProvider", "configuration_option", "get_ctx_defaults")
+__all__ = ("ConfigProvider", "configuration_option", "get_ctx_defaults")
 
 LOG = logging.getLogger(__name__)
 
 
-class TomlProvider:
+class ConfigProvider:
     """
-    A parser for toml configuration files
+    A parser for sam configuration files
     """
 
     def __init__(self, section=None, cmd_names=None):
         """
-        The constructor for TomlProvider class
-        :param section: section defined in the configuration file nested within `cmd`
-        :param cmd_names: cmd_name defined in the configuration file
+        The constructor for ConfigProvider class
+
+        Parameters
+        ----------
+        section
+            The section defined in the configuration file nested within `cmd`
+        cmd_names
+            The cmd_name defined in the configuration file
         """
         self.section = section
         self.cmd_names = cmd_names
 
-    def __call__(self, config_path, config_env, cmd_names):
+    def __call__(self, config_path: Path, config_env: str, cmd_names: List[str]) -> dict:
         """
         Get resolved config based on the `file_path` for the configuration file,
         `config_env` targeted inside the config file and corresponding `cmd_name`
         as denoted by `click`.
 
-        :param config_path: The path of configuration file.
-        :param config_env: The name of the sectional config_env within configuration file.
-        :param list cmd_names: sam command name as defined by click
-        :returns dictionary containing the configuration parameters under specified config_env
+        Parameters
+        ----------
+        config_path: Path
+            The path of configuration file.
+        config_env: str
+            The name of the sectional config_env within configuration file.
+        cmd_names: List[str]
+            The sam command name as defined by click.
+
+        Returns
+        -------
+        dict
+            A dictionary containing the configuration parameters under specified config_env.
         """
 
-        resolved_config = {}
+        resolved_config: dict = {}
 
         # Use default sam config file name if config_path only contain the directory
         config_file_path = (
-            Path(os.path.abspath(config_path)) if config_path else Path(os.getcwd(), DEFAULT_CONFIG_FILE_NAME)
+            Path(os.path.abspath(config_path))
+            if config_path
+            else Path(os.getcwd(), SamConfig.get_default_file(os.getcwd()))
         )
         config_file_name = config_file_path.name
         config_file_dir = config_file_path.parents[0]
@@ -105,32 +123,56 @@ def __call__(self, config_path, config_env, cmd_names):
         return resolved_config
 
 
-def configuration_callback(cmd_name, option_name, saved_callback, provider, ctx, param, value):
+def configuration_callback(
+    cmd_name: str,
+    option_name: str,
+    saved_callback: Optional[Callable],
+    provider: Callable,
+    ctx: click.Context,
+    param: click.Parameter,
+    value,
+):
     """
     Callback for reading the config file.
 
     Also takes care of calling user specified custom callback afterwards.
 
-    :param cmd_name: `sam` command name derived from click.
-    :param option_name: The name of the option. This is used for error messages.
-    :param saved_callback: User-specified callback to be called later.
-    :param provider:  A callable that parses the configuration file and returns a dictionary
+    Parameters
+    ----------
+    cmd_name: str
+        The `sam` command name derived from click.
+    option_name: str
+        The name of the option. This is used for error messages.
+    saved_callback: Optional[Callable]
+        User-specified callback to be called later.
+    provider: Callable
+        A callable that parses the configuration file and returns a dictionary
         of the configuration parameters. Will be called as
         `provider(file_path, config_env, cmd_name)`.
-    :param ctx: Click context
-    :param param: Click parameter
-    :param value: Specified value for config_env
-    :returns specified callback or the specified value for config_env.
+    ctx: click.Context
+        Click context
+    param: click.Parameter
+        Click parameter
+    value
+        Specified value for config_env
+
+    Returns
+    -------
+    The specified callback or the specified value for config_env.
     """
 
     # ctx, param and value are default arguments for click specified callbacks.
     ctx.default_map = ctx.default_map or {}
-    cmd_name = cmd_name or ctx.info_name
+    cmd_name = cmd_name or str(ctx.info_name)
     param.default = None
     config_env_name = ctx.params.get("config_env") or DEFAULT_ENV
 
-    config_file = ctx.params.get("config_file") or DEFAULT_CONFIG_FILE_NAME
     config_dir = getattr(ctx, "samconfig_dir", None) or os.getcwd()
+    config_file = (  # If given by default, check for other `samconfig` extensions first. Else use user-provided value
+        SamConfig.get_default_file(config_dir=config_dir)
+        if getattr(ctx.get_parameter_source("config_file"), "name", "") == ParameterSource.DEFAULT.name
+        else ctx.params.get("config_file") or SamConfig.get_default_file(config_dir=config_dir)
+    )
     # If --config-file is an absolute path, use it, if not, start from config_dir
     config_file_path = config_file if os.path.isabs(config_file) else os.path.join(config_dir, config_file)
     if (
@@ -154,21 +196,35 @@ def configuration_callback(cmd_name, option_name, saved_callback, provider, ctx,
     return saved_callback(ctx, param, config_env_name) if saved_callback else config_env_name
 
 
-def get_ctx_defaults(cmd_name, provider, ctx, config_env_name, config_file=None):
+def get_ctx_defaults(
+    cmd_name: str, provider: Callable, ctx: click.Context, config_env_name: str, config_file: Optional[str] = None
+) -> Any:
     """
     Get the set of the parameters that are needed to be set into the click command.
+
     This function also figures out the command name by looking up current click context's parent
     and constructing the parsed command name that is used in default configuration file.
     If a given cmd_name is start-api, the parsed name is "local_start_api".
     provider is called with `config_file`, `config_env_name` and `parsed_cmd_name`.
 
-    :param cmd_name: `sam` command name
-    :param provider: provider to be called for reading configuration file
-    :param ctx: Click context
-    :param config_env_name: config-env within configuration file, sam configuration file will be relative to the
-                            supplied original template if its path is not specified
-    :param config_file: configuration file name
-    :return: dictionary of defaults for parameters
+    Parameters
+    ----------
+    cmd_name: str
+        The `sam` command name.
+    provider: Callable
+        The provider to be called for reading configuration file.
+    ctx: click.Context
+        Click context
+    config_env_name: str
+        The config-env within configuration file, sam configuration file will be relative to the
+        supplied original template if its path is not specified.
+    config_file: Optional[str]
+        The configuration file name.
+
+    Returns
+    -------
+    Any
+        A dictionary of defaults for parameters.
     """
 
     return provider(config_file, config_env_name, get_cmd_names(cmd_name, ctx))
@@ -180,30 +236,38 @@ def configuration_option(*param_decls, **attrs):
     """
     Adds configuration file support to a click application.
 
-    NOTE: This decorator should be added to the top of parameter chain, right below click.command, before
-          any options are declared.
-
-    Example:
-        >>> @click.command("hello")
-            @configuration_option(provider=TomlProvider(section="parameters"))
-            @click.option('--name', type=click.String)
-            def hello(name):
-                print("Hello " + name)
-
     This will create a hidden click option whose callback function loads configuration parameters from default
     configuration environment [default] in default configuration file [samconfig.toml] in the template file
     directory.
-    :param preconfig_decorator_list: A list of click option decorator which need to place before this function. For
-        exmple, if we want to add option "--config-file" and "--config-env" to allow customized configuration file
+
+    Note
+    ----
+    This decorator should be added to the top of parameter chain, right below click.command, before
+    any options are declared.
+
+    Example
+    -------
+    >>> @click.command("hello")
+        @configuration_option(provider=ConfigProvider(section="parameters"))
+        @click.option('--name', type=click.String)
+        def hello(name):
+            print("Hello " + name)
+
+    Parameters
+    ----------
+    preconfig_decorator_list: list
+        A list of click option decorator which need to place before this function. For
+        example, if we want to add option "--config-file" and "--config-env" to allow customized configuration file
         and configuration environment, we will use configuration_option as below:
         @configuration_option(
             preconfig_decorator_list=[decorator_customize_config_file, decorator_customize_config_env],
-            provider=TomlProvider(section=CONFIG_SECTION),
+            provider=ConfigProvider(section=CONFIG_SECTION),
         )
         By default, we enable these two options.
-    :param provider: A callable that parses the configuration file and returns a dictionary
+    provider: Callable
+        A callable that parses the configuration file and returns a dictionary
         of the configuration parameters. Will be called as
-        `provider(file_path, config_env, cmd_name)
+        `provider(file_path, config_env, cmd_name)`
     """
 
     def decorator_configuration_setup(f):
@@ -240,17 +304,25 @@ def decorator(f):
     return composed_decorator(decorator_list)
 
 
-def decorator_customize_config_file(f):
+def decorator_customize_config_file(f: Callable) -> Callable:
     """
     CLI option to customize configuration file name. By default it is 'samconfig.toml' in project directory.
     Ex: --config-file samconfig.toml
-    :param f: Callback function passed by Click
-    :return: Callback function
+
+    Parameters
+    ----------
+    f: Callable
+        Callback function passed by Click
+
+    Returns
+    -------
+    Callable
+        A Callback function
     """
-    config_file_attrs = {}
+    config_file_attrs: Dict[str, Any] = {}
     config_file_param_decls = ("--config-file",)
     config_file_attrs["help"] = "Configuration file containing default parameter values."
-    config_file_attrs["default"] = "samconfig.toml"
+    config_file_attrs["default"] = DEFAULT_CONFIG_FILE_NAME
     config_file_attrs["show_default"] = True
     config_file_attrs["is_eager"] = True
     config_file_attrs["required"] = False
@@ -258,17 +330,25 @@ def decorator_customize_config_file(f):
     return click.option(*config_file_param_decls, **config_file_attrs)(f)
 
 
-def decorator_customize_config_env(f):
+def decorator_customize_config_env(f: Callable) -> Callable:
     """
     CLI option to customize configuration environment name. By default it is 'default'.
     Ex: --config-env default
-    :param f: Callback function passed by Click
-    :return: Callback function
+
+    Parameters
+    ----------
+    f: Callable
+        Callback function passed by Click
+
+    Returns
+    -------
+    Callable
+        A Callback function
     """
-    config_env_attrs = {}
+    config_env_attrs: Dict[str, Any] = {}
     config_env_param_decls = ("--config-env",)
     config_env_attrs["help"] = "Environment name specifying default parameter values in the configuration file."
-    config_env_attrs["default"] = "default"
+    config_env_attrs["default"] = DEFAULT_ENV
     config_env_attrs["show_default"] = True
     config_env_attrs["is_eager"] = True
     config_env_attrs["required"] = False
diff --git a/samcli/commands/_utils/custom_options/hook_name_option.py b/samcli/commands/_utils/custom_options/hook_name_option.py
index 745ab6c64a..a2cb334157 100644
--- a/samcli/commands/_utils/custom_options/hook_name_option.py
+++ b/samcli/commands/_utils/custom_options/hook_name_option.py
@@ -141,7 +141,7 @@ def _get_customer_input_beta_features_option(default_map, experimental_entry, op
     if beta_features is not None:
         return beta_features
 
-    # Get the beta-features flag value from the SamConfig toml file if provided.
+    # Get the beta-features flag value from the SamConfig file if provided.
     beta_features = default_map.get("beta_features")
     if beta_features is not None:
         return beta_features
diff --git a/samcli/commands/build/command.py b/samcli/commands/build/command.py
index a60f9954e1..86327d411d 100644
--- a/samcli/commands/build/command.py
+++ b/samcli/commands/build/command.py
@@ -27,7 +27,7 @@
 from samcli.cli.main import pass_context, common_options as cli_framework_options, aws_creds_options, print_cmdline_args
 from samcli.commands.build.core.command import BuildCommand
 from samcli.lib.telemetry.metric import track_command
-from samcli.cli.cli_config_file import configuration_option, TomlProvider
+from samcli.cli.cli_config_file import configuration_option, ConfigProvider
 from samcli.lib.utils.version_checker import check_newer_version
 from samcli.commands.build.click_container import ContainerOptions
 from samcli.commands.build.utils import MountMode
@@ -69,7 +69,7 @@
     short_help=HELP_TEXT,
     context_settings={"max_content_width": 120},
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @hook_name_click_option(
     force_prepare=True,
     invalid_coexist_options=["t", "template-file", "template", "parameter-overrides"],
diff --git a/samcli/commands/delete/delete_context.py b/samcli/commands/delete/delete_context.py
index 08d327eceb..1424c87f4a 100644
--- a/samcli/commands/delete/delete_context.py
+++ b/samcli/commands/delete/delete_context.py
@@ -9,7 +9,7 @@
 from botocore.exceptions import NoCredentialsError, NoRegionError
 from click import confirm, prompt
 
-from samcli.cli.cli_config_file import TomlProvider
+from samcli.cli.cli_config_file import ConfigProvider
 from samcli.commands.delete.exceptions import CfDeleteFailedStatusError
 from samcli.commands.exceptions import AWSServiceClientError, RegionError
 from samcli.lib.bootstrap.companion_stack.companion_stack_builder import CompanionStack
@@ -82,8 +82,8 @@ def parse_config_file(self):
         """
         Read the provided config file if it exists and assign the options values.
         """
-        toml_provider = TomlProvider(CONFIG_SECTION, [CONFIG_COMMAND])
-        config_options = toml_provider(
+        config_provider = ConfigProvider(CONFIG_SECTION, [CONFIG_COMMAND])
+        config_options = config_provider(
             config_path=self.config_file, config_env=self.config_env, cmd_names=[CONFIG_COMMAND]
         )
         if not config_options:
diff --git a/samcli/commands/deploy/command.py b/samcli/commands/deploy/command.py
index aeefe4d25f..557a601261 100644
--- a/samcli/commands/deploy/command.py
+++ b/samcli/commands/deploy/command.py
@@ -6,7 +6,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, common_options, pass_context, print_cmdline_args
 from samcli.commands._utils.cdk_support_decorators import unsupported_command_cdk
 from samcli.commands._utils.click_mutex import ClickMutex
@@ -75,7 +75,7 @@
     description=DESCRIPTION,
     requires_credentials=True,
 )
-@configuration_option(provider=TomlProvider(section=CONFIG_SECTION))
+@configuration_option(provider=ConfigProvider(section=CONFIG_SECTION))
 @click.option(
     "--guided",
     "-g",
diff --git a/samcli/commands/deploy/guided_config.py b/samcli/commands/deploy/guided_config.py
index b9d8ea59b5..78866944cd 100644
--- a/samcli/commands/deploy/guided_config.py
+++ b/samcli/commands/deploy/guided_config.py
@@ -7,7 +7,8 @@
 
 from samcli.cli.context import get_cmd_names
 from samcli.commands.deploy.exceptions import GuidedDeployFailedError
-from samcli.lib.config.samconfig import DEFAULT_CONFIG_FILE_NAME, DEFAULT_ENV, SamConfig
+from samcli.lib.config.exceptions import SamConfigFileReadException
+from samcli.lib.config.samconfig import DEFAULT_ENV, SamConfig
 
 
 class GuidedConfig:
@@ -19,20 +20,25 @@ def get_config_ctx(self, config_file=None):
         ctx = click.get_current_context()
 
         samconfig_dir = getattr(ctx, "samconfig_dir", None)
+        config_dir = samconfig_dir if samconfig_dir else SamConfig.config_dir(template_file_path=self.template_file)
         samconfig = SamConfig(
-            config_dir=samconfig_dir if samconfig_dir else SamConfig.config_dir(template_file_path=self.template_file),
-            filename=config_file or DEFAULT_CONFIG_FILE_NAME,
+            config_dir=config_dir,
+            filename=config_file or SamConfig.get_default_file(config_dir=config_dir),
         )
         return ctx, samconfig
 
     def read_config_showcase(self, config_file=None):
-        _, samconfig = self.get_config_ctx(config_file)
-
-        status = "Found" if samconfig.exists() else "Not found"
         msg = (
             "Syntax invalid in samconfig.toml; save values "
             "through sam deploy --guided to overwrite file with a valid set of values."
         )
+        try:
+            _, samconfig = self.get_config_ctx(config_file)
+        except SamConfigFileReadException:
+            raise GuidedDeployFailedError(msg)
+
+        status = "Found" if samconfig.exists() else "Not found"
+
         config_sanity = samconfig.sanity_check()
         click.secho("\nConfiguring SAM deploy\n======================", fg="yellow")
         click.echo(f"\n\tLooking for config file [{config_file}] :  {status}")
diff --git a/samcli/commands/init/command.py b/samcli/commands/init/command.py
index 8702b3f9a9..f31e967a04 100644
--- a/samcli/commands/init/command.py
+++ b/samcli/commands/init/command.py
@@ -7,7 +7,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import common_options, pass_context, print_cmdline_args
 from samcli.commands._utils.click_mutex import ClickMutex
 from samcli.commands.init.core.command import InitCommand
@@ -112,7 +112,7 @@ def wrapped(*args, **kwargs):
     description=DESCRIPTION,
     requires_credentials=False,
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @click.option(
     "--no-interactive",
     is_flag=True,
diff --git a/samcli/commands/list/endpoints/command.py b/samcli/commands/list/endpoints/command.py
index 6de1c41bb2..f11543ef8c 100644
--- a/samcli/commands/list/endpoints/command.py
+++ b/samcli/commands/list/endpoints/command.py
@@ -4,7 +4,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, common_options, pass_context, print_cmdline_args
 from samcli.commands._utils.command_exception_handler import command_exception_handler
 from samcli.commands._utils.options import parameter_override_option, template_option_without_build
@@ -21,7 +21,7 @@
 
 
 @click.command(name="endpoints", help=HELP_TEXT)
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @parameter_override_option
 @stack_name_option
 @output_option
diff --git a/samcli/commands/list/resources/command.py b/samcli/commands/list/resources/command.py
index 5dd2b41034..dacfac30e2 100644
--- a/samcli/commands/list/resources/command.py
+++ b/samcli/commands/list/resources/command.py
@@ -4,7 +4,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, common_options, pass_context, print_cmdline_args
 from samcli.commands._utils.command_exception_handler import command_exception_handler
 from samcli.commands._utils.options import parameter_override_option, template_option_without_build
@@ -20,7 +20,7 @@
 
 
 @click.command(name="resources", help=HELP_TEXT)
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @parameter_override_option
 @stack_name_option
 @output_option
diff --git a/samcli/commands/list/stack_outputs/command.py b/samcli/commands/list/stack_outputs/command.py
index 3800c009b2..e988f98045 100644
--- a/samcli/commands/list/stack_outputs/command.py
+++ b/samcli/commands/list/stack_outputs/command.py
@@ -4,7 +4,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, common_options, pass_context, print_cmdline_args
 from samcli.commands._utils.command_exception_handler import command_exception_handler
 from samcli.commands.list.cli_common.options import output_option
@@ -23,7 +23,7 @@
     required=True,
     type=click.STRING,
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @output_option
 @aws_creds_options
 @common_options
diff --git a/samcli/commands/local/generate_event/event_generation.py b/samcli/commands/local/generate_event/event_generation.py
index 5715bded73..9bf8e49e7a 100644
--- a/samcli/commands/local/generate_event/event_generation.py
+++ b/samcli/commands/local/generate_event/event_generation.py
@@ -6,7 +6,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.options import debug_option
 from samcli.lib.generated_sample_events import events
 from samcli.lib.telemetry.metric import track_command
@@ -160,7 +160,7 @@ def get_command(self, ctx, cmd_name):
             callback=command_callback,
         )
 
-        cmd = configuration_option(provider=TomlProvider(section="parameters"))(debug_option(cmd))
+        cmd = configuration_option(provider=ConfigProvider(section="parameters"))(debug_option(cmd))
         return cmd
 
     def list_commands(self, ctx):
diff --git a/samcli/commands/local/invoke/cli.py b/samcli/commands/local/invoke/cli.py
index a9a3fc9571..0442e7b7ed 100644
--- a/samcli/commands/local/invoke/cli.py
+++ b/samcli/commands/local/invoke/cli.py
@@ -6,7 +6,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
 from samcli.commands._utils.experimental import ExperimentalFlag, is_experimental_enabled
@@ -43,7 +43,7 @@
     short_help=HELP_TEXT,
     context_settings={"max_content_width": 120},
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @hook_name_click_option(
     force_prepare=False, invalid_coexist_options=["t", "template-file", "template", "parameter-overrides"]
 )
diff --git a/samcli/commands/local/start_api/cli.py b/samcli/commands/local/start_api/cli.py
index 9de4d7982c..3e2f02b5f3 100644
--- a/samcli/commands/local/start_api/cli.py
+++ b/samcli/commands/local/start_api/cli.py
@@ -6,7 +6,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
 from samcli.commands._utils.experimental import ExperimentalFlag, is_experimental_enabled
@@ -58,7 +58,7 @@
     requires_credentials=False,
     context_settings={"max_content_width": 120},
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @hook_name_click_option(
     force_prepare=False, invalid_coexist_options=["t", "template-file", "template", "parameter-overrides"]
 )
diff --git a/samcli/commands/local/start_lambda/cli.py b/samcli/commands/local/start_lambda/cli.py
index 9aaec50976..ded8b786fc 100644
--- a/samcli/commands/local/start_lambda/cli.py
+++ b/samcli/commands/local/start_lambda/cli.py
@@ -6,7 +6,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
 from samcli.commands._utils.experimental import ExperimentalFlag, is_experimental_enabled
@@ -52,7 +52,7 @@
     requires_credentials=False,
     context_settings={"max_content_width": 120},
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @hook_name_click_option(
     force_prepare=False, invalid_coexist_options=["t", "template-file", "template", "parameter-overrides"]
 )
diff --git a/samcli/commands/logs/command.py b/samcli/commands/logs/command.py
index 1146767a60..f8df636b59 100644
--- a/samcli/commands/logs/command.py
+++ b/samcli/commands/logs/command.py
@@ -6,7 +6,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
 from samcli.commands._utils.command_exception_handler import command_exception_handler
@@ -49,7 +49,7 @@
     description=DESCRIPTION,
     requires_credentials=True,
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @click.option(
     "--name",
     "-n",
diff --git a/samcli/commands/package/command.py b/samcli/commands/package/command.py
index 41fb10b133..151661c91e 100644
--- a/samcli/commands/package/command.py
+++ b/samcli/commands/package/command.py
@@ -3,7 +3,7 @@
 """
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, common_options, pass_context, print_cmdline_args
 from samcli.commands._utils.cdk_support_decorators import unsupported_command_cdk
 from samcli.commands._utils.command_exception_handler import command_exception_handler
@@ -67,7 +67,7 @@ def resources_and_properties_help_string():
     description=DESCRIPTION,
     requires_credentials=True,
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @template_click_option(include_build=True)
 @click.option(
     "--output-template-file",
diff --git a/samcli/commands/pipeline/bootstrap/cli.py b/samcli/commands/pipeline/bootstrap/cli.py
index 9b7db02578..7ba17e43fe 100644
--- a/samcli/commands/pipeline/bootstrap/cli.py
+++ b/samcli/commands/pipeline/bootstrap/cli.py
@@ -7,7 +7,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, common_options, pass_context, print_cmdline_args
 from samcli.commands._utils.click_mutex import ClickMutex
 from samcli.commands._utils.command_exception_handler import command_exception_handler
@@ -38,7 +38,7 @@
 
 
 @click.command("bootstrap", short_help=SHORT_HELP, help=HELP_TEXT, context_settings=dict(max_content_width=120))
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @click.option(
     "--interactive/--no-interactive",
     is_flag=True,
diff --git a/samcli/commands/pipeline/init/cli.py b/samcli/commands/pipeline/init/cli.py
index 9e42f6e74b..ec675fb608 100644
--- a/samcli/commands/pipeline/init/cli.py
+++ b/samcli/commands/pipeline/init/cli.py
@@ -5,7 +5,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import common_options as cli_framework_options
 from samcli.cli.main import pass_context
 from samcli.commands._utils.command_exception_handler import command_exception_handler
@@ -24,7 +24,7 @@
 
 
 @click.command("init", help=HELP_TEXT, short_help=SHORT_HELP)
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @click.option(
     "--bootstrap",
     is_flag=True,
diff --git a/samcli/commands/publish/command.py b/samcli/commands/publish/command.py
index 091a044192..4ebfb3e8e5 100644
--- a/samcli/commands/publish/command.py
+++ b/samcli/commands/publish/command.py
@@ -7,7 +7,7 @@
 import click
 from serverlessrepo.publish import CREATE_APPLICATION
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
 from samcli.commands._utils.command_exception_handler import command_exception_handler
@@ -44,7 +44,7 @@
 
 
 @click.command("publish", help=HELP_TEXT, short_help=SHORT_HELP)
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @template_common_option
 @click.option("--semantic-version", help=SEMANTIC_VERSION_HELP)
 @aws_creds_options
diff --git a/samcli/commands/remote/invoke/cli.py b/samcli/commands/remote/invoke/cli.py
index 3f3a771ea1..0318566b4a 100644
--- a/samcli/commands/remote/invoke/cli.py
+++ b/samcli/commands/remote/invoke/cli.py
@@ -4,7 +4,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.context import Context
 from samcli.cli.main import aws_creds_options, common_options, pass_context, print_cmdline_args
 from samcli.cli.types import RemoteInvokeOutputFormatType
@@ -42,7 +42,7 @@
     requires_credentials=True,
     context_settings={"max_content_width": 120},
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @click.option("--stack-name", required=False, help="Name of the stack to get the resource information from")
 @click.argument("resource-id", required=False)
 @click.option(
diff --git a/samcli/commands/sync/command.py b/samcli/commands/sync/command.py
index 81f1222207..ddc5e2a165 100644
--- a/samcli/commands/sync/command.py
+++ b/samcli/commands/sync/command.py
@@ -5,7 +5,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.context import Context
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
@@ -114,7 +114,7 @@
     requires_credentials=True,
     context_settings={"max_content_width": 120},
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @template_option_without_build
 @click.option(
     "--code",
diff --git a/samcli/commands/traces/command.py b/samcli/commands/traces/command.py
index 183a2bd156..d82b6871ab 100644
--- a/samcli/commands/traces/command.py
+++ b/samcli/commands/traces/command.py
@@ -5,7 +5,7 @@
 
 import click
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
 from samcli.commands._utils.command_exception_handler import command_exception_handler
@@ -28,7 +28,7 @@
 
 
 @click.command("traces", help=HELP_TEXT, short_help="Fetch AWS X-Ray traces")
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @click.option(
     "--trace-id",
     "-ti",
diff --git a/samcli/commands/validate/validate.py b/samcli/commands/validate/validate.py
index 1c5c2b28b1..221284b1ac 100644
--- a/samcli/commands/validate/validate.py
+++ b/samcli/commands/validate/validate.py
@@ -8,7 +8,7 @@
 from botocore.exceptions import NoCredentialsError
 from samtranslator.translator.arn_generator import NoRegionFound
 
-from samcli.cli.cli_config_file import TomlProvider, configuration_option
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option
 from samcli.cli.context import Context
 from samcli.cli.main import aws_creds_options, pass_context, print_cmdline_args
 from samcli.cli.main import common_options as cli_framework_options
@@ -35,7 +35,7 @@
     requires_credentials=False,
     context_settings={"max_content_width": 120},
 )
-@configuration_option(provider=TomlProvider(section="parameters"))
+@configuration_option(provider=ConfigProvider(section="parameters"))
 @template_option_without_build
 @aws_creds_options
 @cli_framework_options
diff --git a/samcli/lib/config/exceptions.py b/samcli/lib/config/exceptions.py
index 50297ce722..c179b4a13c 100644
--- a/samcli/lib/config/exceptions.py
+++ b/samcli/lib/config/exceptions.py
@@ -4,4 +4,12 @@
 
 
 class SamConfigVersionException(Exception):
-    pass
+    """Exception for the `samconfig` file being not present or in unrecognized format"""
+
+
+class FileParseException(Exception):
+    """Exception when a file is incorrectly parsed by a FileManager object."""
+
+
+class SamConfigFileReadException(Exception):
+    """Exception when a `samconfig` file is read incorrectly."""
diff --git a/samcli/lib/config/file_manager.py b/samcli/lib/config/file_manager.py
new file mode 100644
index 0000000000..0629ace318
--- /dev/null
+++ b/samcli/lib/config/file_manager.py
@@ -0,0 +1,342 @@
+"""
+Class to represent the parsing of different file types into Python objects.
+"""
+
+
+import json
+import logging
+from abc import ABC, abstractmethod
+from pathlib import Path
+from typing import Any, Dict, Type
+
+import tomlkit
+from ruamel.yaml import YAML, YAMLError
+from ruamel.yaml.compat import StringIO
+
+from samcli.lib.config.exceptions import FileParseException
+
+LOG = logging.getLogger(__name__)
+COMMENT_KEY = "__comment__"
+
+
+class FileManager(ABC):
+    """
+    Abstract class to be overridden by file managers for specific file extensions.
+    """
+
+    @staticmethod
+    @abstractmethod
+    def read(filepath: Path) -> Any:
+        """
+        Read a file at a given path.
+
+        Parameters
+        ----------
+        filepath: Path
+            The Path object that points to the file to be read.
+
+        Returns
+        -------
+        Any
+            A dictionary-like representation of the contents at the filepath location.
+        """
+        raise NotImplementedError("Read method not implemented.")
+
+    @staticmethod
+    @abstractmethod
+    def write(document: dict, filepath: Path):
+        """
+        Write a dictionary or dictionary-like object to a given file.
+
+        Parameters
+        ----------
+        document: dict
+            The object to write.
+        filepath: Path
+            The final location for the document to be written.
+        """
+        raise NotImplementedError("Write method not implemented.")
+
+    @staticmethod
+    @abstractmethod
+    def put_comment(document: Any, comment: str) -> Any:
+        """
+        Put a comment in a document object.
+
+        Parameters
+        ----------
+        document: Any
+            The object to write
+        comment: str
+            The comment to include in the document.
+
+        Returns
+        -------
+        Any
+            The new document, with the comment added to it.
+        """
+        raise NotImplementedError("Put comment method not implemented.")
+
+
+class TomlFileManager(FileManager):
+    """
+    Static class to read and write toml files.
+    """
+
+    file_format = "TOML"
+
+    @staticmethod
+    def read(filepath: Path) -> Any:
+        """
+        Read a TOML file at the given path.
+
+        Parameters
+        ----------
+        filepath: Path
+            The Path object that points to the file to be read.
+
+        Returns
+        -------
+        Any
+            A dictionary-like tomlkit.TOMLDocument object, which represents the contents of the TOML file at the
+            provided location.
+        """
+        toml_doc = tomlkit.document()
+        try:
+            txt = filepath.read_text()
+            toml_doc = tomlkit.loads(txt)
+        except OSError as e:
+            LOG.debug(f"OSError occurred while reading {TomlFileManager.file_format} file: {str(e)}")
+        except tomlkit.exceptions.TOMLKitError as e:
+            raise FileParseException(e) from e
+
+        return toml_doc
+
+    @staticmethod
+    def write(document: dict, filepath: Path):
+        """
+        Write the contents of a dictionary or tomlkit.TOMLDocument to a TOML file at the provided location.
+
+        Parameters
+        ----------
+        document: dict
+            The object to write.
+        filepath: Path
+            The final location for the TOML file to be written.
+        """
+        if not document:
+            LOG.debug("Nothing for TomlFileManager to write.")
+            return
+
+        toml_document = TomlFileManager._to_toml(document)
+
+        if toml_document.get(COMMENT_KEY, None):  # Remove dunder comments that may be residue from other formats
+            toml_document.add(tomlkit.comment(toml_document.get(COMMENT_KEY, "")))
+            toml_document.pop(COMMENT_KEY)
+
+        filepath.write_text(tomlkit.dumps(toml_document))
+
+    @staticmethod
+    def put_comment(document: dict, comment: str) -> Any:
+        """
+        Put a comment in a document object.
+
+        Parameters
+        ----------
+        document: Any
+            The tomlkit.TOMLDocument object to write
+        comment: str
+            The comment to include in the document.
+
+        Returns
+        -------
+        Any
+            The new TOMLDocument, with the comment added to it.
+        """
+        document = TomlFileManager._to_toml(document)
+        document.add(tomlkit.comment(comment))
+        return document
+
+    @staticmethod
+    def _to_toml(document: dict) -> tomlkit.TOMLDocument:
+        """Ensure that a dictionary-like object is a TOMLDocument."""
+        return tomlkit.parse(tomlkit.dumps(document))
+
+
+class YamlFileManager(FileManager):
+    """
+    Static class to read and write yaml files.
+    """
+
+    yaml = YAML()
+    file_format = "YAML"
+
+    @staticmethod
+    def read(filepath: Path) -> Any:
+        """
+        Read a YAML file at the given path.
+
+        Parameters
+        ----------
+        filepath: Path
+            The Path object that points to the file to be read.
+
+        Returns
+        -------
+        Any
+            A dictionary-like yaml object, which represents the contents of the YAML file at the
+            provided location.
+        """
+        yaml_doc = {}
+        try:
+            yaml_doc = YamlFileManager.yaml.load(filepath.read_text())
+        except OSError as e:
+            LOG.debug(f"OSError occurred while reading {YamlFileManager.file_format} file: {str(e)}")
+        except YAMLError as e:
+            raise FileParseException(e) from e
+
+        return yaml_doc
+
+    @staticmethod
+    def write(document: dict, filepath: Path):
+        """
+        Write the contents of a dictionary to a YAML file at the provided location.
+
+        Parameters
+        ----------
+        document: dict
+            The object to write.
+        filepath: Path
+            The final location for the YAML file to be written.
+        """
+        if not document:
+            LOG.debug("No document given to YamlFileManager to write.")
+            return
+
+        yaml_doc = YamlFileManager._to_yaml(document)
+
+        if yaml_doc.get(COMMENT_KEY, None):  # Comment appears at the top of doc
+            yaml_doc.yaml_set_start_comment(document[COMMENT_KEY])
+            yaml_doc.pop(COMMENT_KEY)
+
+        YamlFileManager.yaml.dump(yaml_doc, filepath)
+
+    @staticmethod
+    def put_comment(document: Any, comment: str) -> Any:
+        """
+        Put a comment in a document object.
+
+        Parameters
+        ----------
+        document: Any
+            The yaml object to write
+        comment: str
+            The comment to include in the document.
+
+        Returns
+        -------
+        Any
+            The new yaml document, with the comment added to it.
+        """
+        document = YamlFileManager._to_yaml(document)
+        document.yaml_set_start_comment(comment)
+        return document
+
+    @staticmethod
+    def _to_yaml(document: dict) -> Any:
+        """
+        Ensure a dictionary-like object is a YAML document.
+
+        Parameters
+        ----------
+        document: dict
+            A dictionary-like object to parse.
+
+        Returns
+        -------
+        Any
+            A dictionary-like YAML object, as derived from `yaml.load()`.
+        """
+        with StringIO() as stream:
+            YamlFileManager.yaml.dump(document, stream)
+            return YamlFileManager.yaml.load(stream.getvalue())
+
+
+class JsonFileManager(FileManager):
+    """
+    Static class to read and write json files.
+    """
+
+    file_format = "JSON"
+    INDENT_SIZE = 2
+
+    @staticmethod
+    def read(filepath: Path) -> Any:
+        """
+        Read a JSON file at a given path.
+
+        Parameters
+        ----------
+        filepath: Path
+            The Path object that points to the file to be read.
+
+        Returns
+        -------
+        Any
+            A dictionary representation of the contents of the JSON document.
+        """
+        json_file = {}
+        try:
+            json_file = json.loads(filepath.read_text())
+        except OSError as e:
+            LOG.debug(f"OSError occurred while reading {JsonFileManager.file_format} file: {str(e)}")
+        except json.JSONDecodeError as e:
+            raise FileParseException(e) from e
+        return json_file
+
+    @staticmethod
+    def write(document: dict, filepath: Path):
+        """
+        Write a dictionary or dictionary-like object to a JSON file.
+
+        Parameters
+        ----------
+        document: dict
+            The JSON object to write.
+        filepath: Path
+            The final location for the document to be written.
+        """
+        if not document:
+            LOG.debug("No document given to JsonFileManager to write.")
+            return
+
+        with filepath.open("w") as file:
+            json.dump(document, file, indent=JsonFileManager.INDENT_SIZE)
+
+    @staticmethod
+    def put_comment(document: Any, comment: str) -> Any:
+        """
+        Put a comment in a JSON object.
+
+        Parameters
+        ----------
+        document: Any
+            The JSON object to write
+        comment: str
+            The comment to include in the document.
+
+        Returns
+        -------
+        Any
+            The new JSON dictionary object, with the comment added to it.
+        """
+        document.update({COMMENT_KEY: comment})
+        return document
+
+
+FILE_MANAGER_MAPPER: Dict[str, Type[FileManager]] = {  # keys ordered by priority
+    ".toml": TomlFileManager,
+    ".yaml": YamlFileManager,
+    ".yml": YamlFileManager,
+    # ".json": JsonFileManager,  # JSON support disabled
+}
diff --git a/samcli/lib/config/samconfig.py b/samcli/lib/config/samconfig.py
index e48e53d625..e9acafd557 100644
--- a/samcli/lib/config/samconfig.py
+++ b/samcli/lib/config/samconfig.py
@@ -7,26 +7,25 @@
 from pathlib import Path
 from typing import Any, Iterable
 
-import tomlkit
-
-from samcli.lib.config.exceptions import SamConfigVersionException
+from samcli.lib.config.exceptions import FileParseException, SamConfigFileReadException, SamConfigVersionException
+from samcli.lib.config.file_manager import FILE_MANAGER_MAPPER
 from samcli.lib.config.version import SAM_CONFIG_VERSION, VERSION_KEY
+from samcli.lib.telemetry.event import EventTracker
 
 LOG = logging.getLogger(__name__)
 
-DEFAULT_CONFIG_FILE_EXTENSION = "toml"
-DEFAULT_CONFIG_FILE_NAME = f"samconfig.{DEFAULT_CONFIG_FILE_EXTENSION}"
+DEFAULT_CONFIG_FILE_EXTENSION = ".toml"
+DEFAULT_CONFIG_FILE = "samconfig"
+DEFAULT_CONFIG_FILE_NAME = DEFAULT_CONFIG_FILE + DEFAULT_CONFIG_FILE_EXTENSION
 DEFAULT_ENV = "default"
 DEFAULT_GLOBAL_CMDNAME = "global"
 
 
 class SamConfig:
     """
-    Class to interface with `samconfig.toml` file.
+    Class to represent `samconfig` config options.
     """
 
-    document = None
-
     def __init__(self, config_dir, filename=None):
         """
         Initialize the class
@@ -39,11 +38,23 @@ def __init__(self, config_dir, filename=None):
             Optional. Name of the configuration file. It is recommended to stick with default so in the future we
             could automatically support auto-resolving multiple config files within same directory.
         """
-        self.filepath = Path(config_dir, filename or DEFAULT_CONFIG_FILE_NAME)
+        self.document = {}
+        self.filepath = Path(config_dir, filename or self.get_default_file(config_dir=config_dir))
+        file_extension = self.filepath.suffix
+        self.file_manager = FILE_MANAGER_MAPPER.get(file_extension, None)
+        if not self.file_manager:
+            LOG.warning(
+                f"The config file extension '{file_extension}' is not supported. "
+                f"Supported formats are: [{'|'.join(FILE_MANAGER_MAPPER.keys())}]"
+            )
+            raise SamConfigFileReadException(
+                f"The config file {self.filepath} uses an unsupported extension, and cannot be read."
+            )
+        self._read()
+        EventTracker.track_event("SamConfigFileExtension", file_extension)
 
     def get_stage_configuration_names(self):
-        self._read()
-        if isinstance(self.document, dict):
+        if self.document:
             return [stage for stage, value in self.document.items() if isinstance(value, dict)]
         return []
 
@@ -69,23 +80,19 @@ def get_all(self, cmd_names, section, env=DEFAULT_ENV):
         ------
         KeyError
             If the config file does *not* have the specific section
-
-        tomlkit.exceptions.TOMLKitError
-            If the configuration file is invalid
         """
 
         env = env or DEFAULT_ENV
 
-        self._read()
-        if isinstance(self.document, dict):
-            toml_content = self.document.get(env, {})
-            params = toml_content.get(self._to_key(cmd_names), {}).get(section, {})
-            if DEFAULT_GLOBAL_CMDNAME in toml_content:
-                global_params = toml_content.get(DEFAULT_GLOBAL_CMDNAME, {}).get(section, {})
-                global_params.update(params.copy())
-                params = global_params.copy()
-            return params
-        return {}
+        self.document = self._read()
+
+        config_content = self.document.get(env, {})
+        params = config_content.get(self._to_key(cmd_names), {}).get(section, {})
+        if DEFAULT_GLOBAL_CMDNAME in config_content:
+            global_params = config_content.get(DEFAULT_GLOBAL_CMDNAME, {}).get(section, {})
+            global_params.update(params.copy())
+            params = global_params.copy()
+        return params
 
     def put(self, cmd_names, section, key, value, env=DEFAULT_ENV):
         """
@@ -102,20 +109,10 @@ def put(self, cmd_names, section, key, value, env=DEFAULT_ENV):
         key : str
             Key to write the data under
         value : Any
-            Value to write. Could be any of the supported TOML types.
+            Value to write. Could be any of the supported types.
         env : str
             Optional, Name of the environment
-
-        Raises
-        ------
-        tomlkit.exceptions.TOMLKitError
-            If the data is invalid
         """
-
-        if self.document is None:
-            # Checking for None here since a TOMLDocument can include a
-            # 'body' property but still be falsy without a 'value' property
-            self._read()
         # Empty document prepare the initial structure.
         # self.document is a nested dict, we need to check each layer and add new tables, otherwise duplicated key
         # in parent layer will override the whole child layer
@@ -144,20 +141,12 @@ def put_comment(self, comment):
         comment: str
             A comment to write to the samconfg file
         """
-        if self.document is None:
-            self._read()
 
-        self.document.add(tomlkit.comment(comment))
+        self.document = self.file_manager.put_comment(self.document, comment)
 
     def flush(self):
         """
         Write the data back to file
-
-        Raises
-        ------
-        tomlkit.exceptions.TOMLKitError
-            If the data is invalid
-
         """
         self._write()
 
@@ -167,7 +156,7 @@ def sanity_check(self):
         """
         try:
             self._read()
-        except tomlkit.exceptions.TOMLKitError:
+        except SamConfigFileReadException:
             return False
         else:
             return True
@@ -196,13 +185,10 @@ def config_dir(template_file_path=None):
     def _read(self):
         if not self.document:
             try:
-                txt = self.filepath.read_text()
-                self.document = tomlkit.loads(txt)
-                self._version_sanity_check(self._version())
-            except OSError:
-                self.document = tomlkit.document()
-
-        if self.document.body:
+                self.document = self.file_manager.read(self.filepath)
+            except FileParseException as e:
+                raise SamConfigFileReadException(e) from e
+        if self.document:
             self._version_sanity_check(self._version())
         return self.document
 
@@ -213,12 +199,9 @@ def _write(self):
         self._ensure_exists()
 
         current_version = self._version() if self._version() else SAM_CONFIG_VERSION
-        try:
-            self.document.add(VERSION_KEY, current_version)
-        except tomlkit.exceptions.KeyAlreadyPresent:
-            # NOTE(TheSriram): Do not attempt to re-write an existing version
-            pass
-        self.filepath.write_text(tomlkit.dumps(self.document))
+        self.document.update({VERSION_KEY: current_version})
+
+        self.file_manager.write(self.document, self.filepath)
 
     def _version(self):
         return self.document.get(VERSION_KEY, None)
@@ -261,6 +244,40 @@ def _deduplicate_global_parameters(self, cmd_name_key, section, key, env=DEFAULT
             # Only keep the global parameter
             del self.document[env][cmd_name_key][section][key]
 
+    @staticmethod
+    def get_default_file(config_dir: str) -> str:
+        """Return a defaultly-named config file, if it exists, otherwise the current default.
+
+        Parameters
+        ----------
+        config_dir: str
+            The name of the directory where the config file is/will be stored.
+
+        Returns
+        -------
+        str
+            The name of the config file found, if it exists. In the case that it does not exist, the default config
+            file name is returned instead.
+        """
+        config_files_found = 0
+        config_file = DEFAULT_CONFIG_FILE_NAME
+
+        for extension in reversed(list(FILE_MANAGER_MAPPER.keys())):
+            filename = DEFAULT_CONFIG_FILE + extension
+            if Path(config_dir, filename).exists():
+                config_files_found += 1
+                config_file = filename
+
+        if config_files_found == 0:  # Config file doesn't exist (yet!)
+            LOG.debug("No config file found in this directory.")
+        elif config_files_found > 1:  # Multiple config files; let user know which is used
+            LOG.info(
+                f"More than one samconfig file found; using {config_file}."
+                f" To use another config file, please specify it using the '--config-file' flag."
+            )
+
+        return config_file
+
     @staticmethod
     def _version_sanity_check(version: Any) -> None:
         if not isinstance(version, float):
diff --git a/samcli/lib/telemetry/event.py b/samcli/lib/telemetry/event.py
index 2d819e37bf..2c35748951 100644
--- a/samcli/lib/telemetry/event.py
+++ b/samcli/lib/telemetry/event.py
@@ -11,6 +11,7 @@
 
 from samcli.cli.context import Context
 from samcli.lib.build.workflows import ALL_CONFIGS
+from samcli.lib.config.file_manager import FILE_MANAGER_MAPPER
 from samcli.lib.telemetry.telemetry import Telemetry
 from samcli.local.common.runtime_template import INIT_RUNTIMES
 
@@ -26,6 +27,7 @@ class EventName(Enum):
     SYNC_FLOW_START = "SyncFlowStart"
     SYNC_FLOW_END = "SyncFlowEnd"
     BUILD_WORKFLOW_USED = "BuildWorkflowUsed"
+    CONFIG_FILE_EXTENSION = "SamConfigFileExtension"
 
 
 class UsedFeature(Enum):
@@ -69,6 +71,7 @@ class EventType:
         EventName.SYNC_FLOW_START: _SYNC_FLOWS,
         EventName.SYNC_FLOW_END: _SYNC_FLOWS,
         EventName.BUILD_WORKFLOW_USED: _WORKFLOWS,
+        EventName.CONFIG_FILE_EXTENSION: list(FILE_MANAGER_MAPPER.keys()),
     }
 
     @staticmethod
diff --git a/tests/integration/buildcmd/build_integ_base.py b/tests/integration/buildcmd/build_integ_base.py
index 13ba14f310..2dab556843 100644
--- a/tests/integration/buildcmd/build_integ_base.py
+++ b/tests/integration/buildcmd/build_integ_base.py
@@ -83,6 +83,7 @@ def get_command_list(
         beta_features=None,
         build_in_source=None,
         mount_with=None,
+        config_file=None,
     ):
         command_list = [self.cmd, "build"]
 
@@ -146,6 +147,9 @@ def get_command_list(
         if build_in_source is not None:
             command_list += ["--build-in-source"] if build_in_source else ["--no-build-in-source"]
 
+        if config_file is not None:
+            command_list += ["--config-file", config_file]
+
         return command_list
 
     def verify_docker_container_cleanedup(self, runtime):
diff --git a/tests/integration/buildcmd/test_build_samconfig.py b/tests/integration/buildcmd/test_build_samconfig.py
new file mode 100644
index 0000000000..3df5052599
--- /dev/null
+++ b/tests/integration/buildcmd/test_build_samconfig.py
@@ -0,0 +1,114 @@
+import os
+from pathlib import Path
+from parameterized import parameterized, parameterized_class
+
+from tests.integration.buildcmd.build_integ_base import BuildIntegBase
+from tests.testing_utils import run_command
+
+
+configs = {
+    ".toml": "samconfig/samconfig.toml",
+    ".yaml": "samconfig/samconfig.yaml",
+    ".yml": "samconfig/samconfig.yml",
+    ".json": "samconfig/samconfig.json",
+}
+
+
+class TestSamConfigWithBuild(BuildIntegBase):
+    @parameterized.expand(
+        [
+            (".toml"),
+            (".yaml"),
+            # (".json"),
+        ]
+    )
+    def test_samconfig_works_with_extension(self, extension):
+        cmdlist = self.get_command_list(config_file=configs[extension])
+
+        command_result = run_command(cmdlist, cwd=self.working_dir)
+        stdout = str(command_result[1])
+        stderr = str(command_result[2])
+
+        self.assertEqual(command_result.process.returncode, 0, "Build should succeed")
+        self.assertIn(
+            f"Built Artifacts  : {extension}",
+            stdout,
+            f"Build template should use build_dir from samconfig{extension}",
+        )
+        self.assertIn("Starting Build use cache", stderr, f"'cache'=true should be set in samconfig{extension}")
+
+    @parameterized.expand(
+        [
+            (".toml"),
+            (".yaml"),
+            # (".json"),
+        ]
+    )
+    def test_samconfig_parameters_are_overridden(self, extension):
+        overrides = {"Runtime": "python3.8"}
+        overridden_build_dir = f"override_{extension}"
+
+        cmdlist = self.get_command_list(
+            config_file=configs[extension], parameter_overrides=overrides, build_dir=overridden_build_dir
+        )
+
+        command_result = run_command(cmdlist, cwd=self.working_dir)
+        stdout = str(command_result[1])
+        stderr = str(command_result[2])
+
+        self.assertEqual(command_result.process.returncode, 0, "Build should succeed")
+        self.assertNotIn(
+            f"Built Artifacts  : {extension}",
+            stdout,
+            f"Build template should not use build_dir from samconfig{extension}",
+        )
+        self.assertIn(
+            f"Built Artifacts  : {overridden_build_dir}", stdout, f"Build template should use overridden build_dir"
+        )
+        self.assertIn("Starting Build use cache", stderr, f"'cache'=true should be set in samconfig{extension}")
+        self.assertNotIn("python3.9", stderr, f"parameter_overrides runtime should not read from samconfig{extension}")
+        self.assertIn(overrides["Runtime"], stderr, "parameter_overrides should use overridden runtime")
+        self.assertNotIn("SomeURI", stderr, f"parameter_overrides should not read ANY values from samconfig{extension}")
+
+
+@parameterized_class(
+    [  # Ordered by expected priority
+        {"extensions": [".toml", ".yaml", ".yml"]},
+        {"extensions": [".yaml", ".yml"]},
+    ]
+)
+class TestSamConfigExtensionHierarchy(BuildIntegBase):
+    def setUp(self):
+        super().setUp()
+        new_template_location = Path(self.working_dir, "template.yaml")
+        new_template_location.write_text(Path(self.template_path).read_text())
+        for extension in self.extensions:
+            config_contents = Path(self.test_data_path, configs[extension]).read_text()
+            new_path = Path(self.working_dir, f"samconfig{extension}")
+            new_path.write_text(config_contents)
+            self.assertTrue(new_path.exists(), f"File samconfig{extension} should have been created in cwd")
+
+    def tearDown(self):
+        for extension in self.extensions:
+            config_path = Path(self.working_dir, f"samconfig{extension}")
+            os.remove(config_path)
+        super().tearDown()
+
+    def test_samconfig_pulls_correct_file_if_multiple(self):
+        self.template_path = str(Path(self.working_dir, "template.yaml"))
+        cmdlist = self.get_command_list(debug=True)
+        command_result = run_command(cmdlist, cwd=self.working_dir)
+        stdout = str(command_result[1])
+
+        self.assertEqual(command_result.process.returncode, 0, "Build should succeed")
+        self.assertIn(
+            f" {self.extensions[0]}",
+            stdout,
+            f"samconfig{self.extensions[0]} should take priority in current test group",
+        )
+        for other_extension in self.extensions[1:]:
+            self.assertNotIn(
+                f" {other_extension}",
+                stdout,
+                f"samconfig{other_extension} should not be read over another, higher priority extension",
+            )
diff --git a/tests/integration/deploy/deploy_integ_base.py b/tests/integration/deploy/deploy_integ_base.py
index f48eae9d61..4db4e5ff6a 100644
--- a/tests/integration/deploy/deploy_integ_base.py
+++ b/tests/integration/deploy/deploy_integ_base.py
@@ -2,11 +2,13 @@
 import tempfile
 from pathlib import Path
 from enum import Enum, auto
+from typing import List, Optional
 
 import boto3
 from botocore.config import Config
 
 from samcli.lib.bootstrap.bootstrap import SAM_CLI_STACK_NAME
+from samcli.lib.config.samconfig import SamConfig
 from tests.integration.package.package_integ_base import PackageIntegBase
 from tests.testing_utils import get_sam_command, run_command, run_command_with_input
 
@@ -212,3 +214,26 @@ def get_minimal_build_command_list(template_file=None, build_dir=None):
             command_list = command_list + ["--build-dir", str(build_dir)]
 
         return command_list
+
+    def _assert_deploy_samconfig_parameters(
+        self,
+        config: SamConfig,
+        stack_name: str = SAM_CLI_STACK_NAME,
+        resolve_s3: bool = True,
+        region: str = "us-east-1",
+        capabilities: str = "CAPABILITY_IAM",
+        confirm_changeset: Optional[bool] = None,
+        parameter_overrides: Optional[str] = None,
+    ):
+        params = config.document["default"]["deploy"]["parameters"]
+
+        self.assertEqual(params["stack_name"], stack_name)
+        self.assertEqual(params["resolve_s3"], resolve_s3)
+        self.assertEqual(params["region"], region)
+        self.assertEqual(params["capabilities"], capabilities)
+
+        if confirm_changeset is not None:
+            self.assertEqual(params["confirm_changeset"], confirm_changeset)
+
+        if parameter_overrides is not None:
+            self.assertEqual(params["parameter_overrides"], parameter_overrides)
diff --git a/tests/integration/deploy/test_deploy_command.py b/tests/integration/deploy/test_deploy_command.py
index 131d3969ab..a7ece04a5c 100644
--- a/tests/integration/deploy/test_deploy_command.py
+++ b/tests/integration/deploy/test_deploy_command.py
@@ -10,7 +10,7 @@
 from parameterized import parameterized
 
 from samcli.lib.bootstrap.bootstrap import SAM_CLI_STACK_NAME
-from samcli.lib.config.samconfig import DEFAULT_CONFIG_FILE_NAME
+from samcli.lib.config.samconfig import DEFAULT_CONFIG_FILE_NAME, SamConfig
 from tests.integration.deploy.deploy_integ_base import DeployIntegBase
 from tests.testing_utils import RUNNING_ON_CI, RUNNING_TEST_FOR_MASTER_ON_CI, RUN_BY_CANARY, UpdatableSARTemplate
 
@@ -613,6 +613,13 @@ def test_deploy_guided_zip(self, template_file):
         # Deploy should succeed with a managed stack
         self.assertEqual(deploy_process_execute.process.returncode, 0)
         self.stacks.append({"name": SAM_CLI_STACK_NAME})
+        # Verify the contents in samconfig
+        config = SamConfig(self.test_data_path)
+        deploy_config_params = config.document["default"]["deploy"]["parameters"]
+        self.assertEqual(deploy_config_params["stack_name"], stack_name)
+        self.assertTrue(deploy_config_params["resolve_s3"])
+        self.assertEqual(deploy_config_params["region"], "us-east-1")
+        self.assertEqual(deploy_config_params["capabilities"], "CAPABILITY_IAM")
         # Remove samconfig.toml
         os.remove(self.test_data_path.joinpath(DEFAULT_CONFIG_FILE_NAME))
 
@@ -627,7 +634,7 @@ def test_deploy_guided_image_auto(self, template_file):
         deploy_command_list = self.get_deploy_command_list(template_file=template_path, guided=True)
 
         deploy_process_execute = self.run_command_with_input(
-            deploy_command_list, f"{stack_name}\n\n\n\n\ny\n\n\ny\n\n\n\n".encode()
+            deploy_command_list, f"{stack_name}\n\n\n\n\ny\n\n\n\n\n\n\n".encode()
         )
 
         # Deploy should succeed with a managed stack
@@ -638,6 +645,10 @@ def test_deploy_guided_image_auto(self, template_file):
         self._assert_companion_stack(self.cfn_client, companion_stack_name)
         self._assert_companion_stack_content(self.ecr_client, companion_stack_name)
 
+        # Verify the contents in samconfig
+        config = SamConfig(self.test_data_path)
+        self._assert_deploy_samconfig_parameters(config, stack_name=stack_name)
+
         # Remove samconfig.toml
         os.remove(self.test_data_path.joinpath(DEFAULT_CONFIG_FILE_NAME))
 
@@ -669,6 +680,9 @@ def test_deploy_guided_image_specify(self, template_file, does_ask_for_authoriza
             self.fail("Companion stack was created. This should not happen with specifying image repos.")
 
         self.stacks.append({"name": SAM_CLI_STACK_NAME})
+        # Verify the contents in samconfig
+        config = SamConfig(self.test_data_path)
+        self._assert_deploy_samconfig_parameters(config, stack_name=stack_name)
         # Remove samconfig.toml
         os.remove(self.test_data_path.joinpath(DEFAULT_CONFIG_FILE_NAME))
 
@@ -690,6 +704,11 @@ def test_deploy_guided_set_parameter(self, template_file):
         # Deploy should succeed with a managed stack
         self.assertEqual(deploy_process_execute.process.returncode, 0)
         self.stacks.append({"name": SAM_CLI_STACK_NAME})
+        # Verify the contents in samconfig
+        config = SamConfig(self.test_data_path)
+        self._assert_deploy_samconfig_parameters(
+            config, stack_name=stack_name, parameter_overrides='Parameter="SuppliedParameter"'
+        )
         # Remove samconfig.toml
         os.remove(self.test_data_path.joinpath(DEFAULT_CONFIG_FILE_NAME))
 
@@ -710,6 +729,14 @@ def test_deploy_guided_set_capabilities(self, template_file):
         # Deploy should succeed with a managed stack
         self.assertEqual(deploy_process_execute.process.returncode, 0)
         self.stacks.append({"name": SAM_CLI_STACK_NAME})
+        # Verify the contents in samconfig
+        config = SamConfig(self.test_data_path)
+        self._assert_deploy_samconfig_parameters(
+            config,
+            stack_name=stack_name,
+            capabilities="CAPABILITY_IAM CAPABILITY_NAMED_IAM",
+            parameter_overrides='Parameter="SuppliedParameter"',
+        )
         # Remove samconfig.toml
         os.remove(self.test_data_path.joinpath(DEFAULT_CONFIG_FILE_NAME))
 
@@ -731,6 +758,11 @@ def test_deploy_guided_capabilities_default(self, template_file):
         # Deploy should succeed with a managed stack
         self.assertEqual(deploy_process_execute.process.returncode, 0)
         self.stacks.append({"name": SAM_CLI_STACK_NAME})
+        # Verify the contents in samconfig
+        config = SamConfig(self.test_data_path)
+        self._assert_deploy_samconfig_parameters(
+            config, stack_name=stack_name, parameter_overrides='Parameter="SuppliedParameter"'
+        )
         # Remove samconfig.toml
         os.remove(self.test_data_path.joinpath(DEFAULT_CONFIG_FILE_NAME))
 
@@ -752,6 +784,11 @@ def test_deploy_guided_set_confirm_changeset(self, template_file):
         # Deploy should succeed with a managed stack
         self.assertEqual(deploy_process_execute.process.returncode, 0)
         self.stacks.append({"name": SAM_CLI_STACK_NAME})
+        # Verify the contents in samconfig
+        config = SamConfig(self.test_data_path)
+        self._assert_deploy_samconfig_parameters(
+            config, stack_name=stack_name, confirm_changeset=True, parameter_overrides='Parameter="SuppliedParameter"'
+        )
         # Remove samconfig.toml
         os.remove(self.test_data_path.joinpath(DEFAULT_CONFIG_FILE_NAME))
 
@@ -789,7 +826,7 @@ def test_deploy_with_invalid_config(self, template_file, config_file):
 
         deploy_process_execute = self.run_command(deploy_command_list)
         self.assertEqual(deploy_process_execute.process.returncode, 1)
-        self.assertIn("Error reading configuration: Unexpected character", str(deploy_process_execute.stderr))
+        self.assertIn("SamConfigFileReadException: Unexpected character", str(deploy_process_execute.stderr))
 
     @parameterized.expand([("aws-serverless-function.yaml", "samconfig-tags-list.toml")])
     def test_deploy_with_valid_config_tags_list(self, template_file, config_file):
diff --git a/tests/integration/telemetry/test_experimental_metric.py b/tests/integration/telemetry/test_experimental_metric.py
index 977e65053f..702ceb4a5f 100644
--- a/tests/integration/telemetry/test_experimental_metric.py
+++ b/tests/integration/telemetry/test_experimental_metric.py
@@ -211,8 +211,11 @@ def test_must_send_not_experimental_metrics_if_not_experimental(self):
 
             self.assertEqual(process.returncode, 2, "Command should fail")
             all_requests = server.get_all_requests()
-            self.assertEqual(1, len(all_requests), "Command run metric must be sent")
-            request = all_requests[0]
+            self.assertEqual(2, len(all_requests), "Command run and event metrics must be sent")
+            # NOTE: Since requests happen asynchronously, we cannot guarantee whether the
+            # commandRun metric will be first or second, so we sort for consistency.
+            all_requests.sort(key=lambda x: list(x["data"]["metrics"][0].keys())[0])
+            request = all_requests[0]  # "commandRun" comes before "events"
             self.assertIn("Content-Type", request["headers"])
             self.assertEqual(request["headers"]["Content-Type"], "application/json")
 
diff --git a/tests/integration/telemetry/test_installed_metric.py b/tests/integration/telemetry/test_installed_metric.py
index e17459828c..725a2d0ff5 100644
--- a/tests/integration/telemetry/test_installed_metric.py
+++ b/tests/integration/telemetry/test_installed_metric.py
@@ -24,7 +24,9 @@ def test_send_installed_metric_on_first_run(self):
             self.assertIn(EXPECTED_TELEMETRY_PROMPT, stderrdata.decode())
 
             all_requests = server.get_all_requests()
-            self.assertEqual(2, len(all_requests), "There should be exactly two metrics request")
+            self.assertEqual(
+                3, len(all_requests), "There should be exactly three metrics request"
+            )  # 3 = 2 expected + events
 
             # First one is usually the installed metric
             requests = filter_installed_metric_requests(all_requests)
diff --git a/tests/integration/telemetry/test_telemetry_contract.py b/tests/integration/telemetry/test_telemetry_contract.py
index 08b3585b99..a3e383bb5d 100644
--- a/tests/integration/telemetry/test_telemetry_contract.py
+++ b/tests/integration/telemetry/test_telemetry_contract.py
@@ -28,7 +28,9 @@ def test_must_not_send_metrics_if_disabled_using_envvar(self):
 
             self.assertEqual(process.returncode, 0, "Command should successfully complete")
             all_requests = server.get_all_requests()
-            self.assertEqual(1, len(all_requests), "Command run metric should be sent")
+            self.assertEqual(
+                2, len(all_requests), "Command run and event metrics should be sent"
+            )  # 2 = cmd_run + events
 
     def test_must_send_metrics_if_enabled_via_envvar(self):
         """
@@ -52,7 +54,7 @@ def test_must_send_metrics_if_enabled_via_envvar(self):
 
             self.assertEqual(process.returncode, 0, "Command should successfully complete")
             all_requests = server.get_all_requests()
-            self.assertEqual(1, len(all_requests), "Command run metric must be sent")
+            self.assertEqual(2, len(all_requests), "Command run and event metrics must be sent")  # cmd_run + events
 
     def test_must_not_crash_when_offline(self):
         """
diff --git a/tests/integration/testdata/buildcmd/samconfig/samconfig.json b/tests/integration/testdata/buildcmd/samconfig/samconfig.json
new file mode 100644
index 0000000000..6fa18e1c11
--- /dev/null
+++ b/tests/integration/testdata/buildcmd/samconfig/samconfig.json
@@ -0,0 +1,12 @@
+{
+  "version": 0.1,
+  "default": {
+    "build": {
+      "parameters": {
+        "build_dir": ".json",
+        "cached": true,
+        "parameter_overrides": "Runtime=python3.9 CodeUri=SomeURI Handler=SomeHandler"
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/integration/testdata/buildcmd/samconfig/samconfig.toml b/tests/integration/testdata/buildcmd/samconfig/samconfig.toml
new file mode 100644
index 0000000000..23a769ff5e
--- /dev/null
+++ b/tests/integration/testdata/buildcmd/samconfig/samconfig.toml
@@ -0,0 +1,5 @@
+version = 0.1
+[default.build.parameters]
+build_dir = ".toml"
+cached = true
+parameter_overrides = "Runtime=python3.9 CodeUri=SomeURI Handler=SomeHandler"
\ No newline at end of file
diff --git a/tests/integration/testdata/buildcmd/samconfig/samconfig.yaml b/tests/integration/testdata/buildcmd/samconfig/samconfig.yaml
new file mode 100644
index 0000000000..63af206238
--- /dev/null
+++ b/tests/integration/testdata/buildcmd/samconfig/samconfig.yaml
@@ -0,0 +1,7 @@
+version: 0.1
+default:
+  build:
+    parameters:
+      build_dir: .yaml
+      cached: true
+      parameter_overrides: Runtime=python3.9 CodeUri=SomeURI Handler=SomeHandler
\ No newline at end of file
diff --git a/tests/integration/testdata/buildcmd/samconfig/samconfig.yml b/tests/integration/testdata/buildcmd/samconfig/samconfig.yml
new file mode 100644
index 0000000000..4af8baa434
--- /dev/null
+++ b/tests/integration/testdata/buildcmd/samconfig/samconfig.yml
@@ -0,0 +1,7 @@
+version: 0.1
+default:
+  build:
+    parameters:
+      build_dir: .yml
+      cached: true
+      parameter_overrides: Runtime=python3.9 CodeUri=SomeURI Handler=SomeHandler
\ No newline at end of file
diff --git a/tests/integration/testdata/buildcmd/samconfig/template.yaml b/tests/integration/testdata/buildcmd/samconfig/template.yaml
new file mode 100644
index 0000000000..6944799912
--- /dev/null
+++ b/tests/integration/testdata/buildcmd/samconfig/template.yaml
@@ -0,0 +1,37 @@
+AWSTemplateFormatVersion : '2010-09-09'
+Transform: AWS::Serverless-2016-10-31
+
+Parameters:
+  Runtime:
+    Type: String
+  CodeUri:
+    Type: String
+  Handler:
+    Type: String
+
+Resources:
+
+  Function:
+    Type: AWS::Serverless::Function
+    Properties:
+      Handler: !Ref Handler
+      Runtime: !Ref Runtime
+      CodeUri: !Ref CodeUri
+      Timeout: 600
+
+
+  OtherRelativePathResource:
+    Type: AWS::ApiGateway::RestApi
+    Properties:
+      BodyS3Location: SomeRelativePath
+
+  GlueResource:
+    Type: AWS::Glue::Job
+    Properties:
+      Command:
+        ScriptLocation: SomeRelativePath
+
+  ExampleNestedStack:
+    Type: AWS::CloudFormation::Stack
+    Properties:
+      TemplateURL: https://s3.amazonaws.com/examplebucket/exampletemplate.yml
diff --git a/tests/unit/cli/test_cli_config_file.py b/tests/unit/cli/test_cli_config_file.py
index 606e0a004e..19bfcfa011 100644
--- a/tests/unit/cli/test_cli_config_file.py
+++ b/tests/unit/cli/test_cli_config_file.py
@@ -5,8 +5,11 @@
 from unittest import TestCase, skipIf
 from unittest.mock import MagicMock, patch
 
+import tomlkit
+
 from samcli.commands.exceptions import ConfigException
-from samcli.cli.cli_config_file import TomlProvider, configuration_option, configuration_callback, get_ctx_defaults
+from samcli.cli.cli_config_file import ConfigProvider, configuration_option, configuration_callback, get_ctx_defaults
+from samcli.lib.config.exceptions import SamConfigFileReadException, SamConfigVersionException
 from samcli.lib.config.samconfig import DEFAULT_ENV
 
 from tests.testing_utils import IS_WINDOWS
@@ -21,9 +24,9 @@ def __init__(self, info_name, parent, params=None, command=None, default_map=Non
         self.default_map = default_map
 
 
-class TestTomlProvider(TestCase):
+class TestConfigProvider(TestCase):
     def setUp(self):
-        self.toml_provider = TomlProvider()
+        self.config_provider = ConfigProvider()
         self.config_env = "config_env"
         self.parameters = "parameters"
         self.cmd_name = "topic"
@@ -33,29 +36,30 @@ def test_toml_valid_with_section(self):
         config_path = Path(config_dir, "samconfig.toml")
         config_path.write_text("version=0.1\n[config_env.topic.parameters]\nword='clarity'\n")
         self.assertEqual(
-            TomlProvider(section=self.parameters)(config_path, self.config_env, [self.cmd_name]), {"word": "clarity"}
+            ConfigProvider(section=self.parameters)(config_path, self.config_env, [self.cmd_name]), {"word": "clarity"}
         )
 
     def test_toml_valid_with_no_version(self):
         config_dir = tempfile.gettempdir()
         config_path = Path(config_dir, "samconfig.toml")
         config_path.write_text("[config_env.topic.parameters]\nword='clarity'\n")
-        with self.assertRaises(ConfigException):
-            TomlProvider(section=self.parameters)(config_path, self.config_env, [self.cmd_name])
+        with self.assertRaises(SamConfigVersionException):
+            ConfigProvider(section=self.parameters)(config_path, self.config_env, [self.cmd_name])
 
     def test_toml_valid_with_invalid_version(self):
         config_dir = tempfile.gettempdir()
         config_path = Path(config_dir, "samconfig.toml")
         config_path.write_text("version='abc'\n[config_env.topic.parameters]\nword='clarity'\n")
-        with self.assertRaises(ConfigException):
-            TomlProvider(section=self.parameters)(config_path, self.config_env, [self.cmd_name])
+        with self.assertRaises(SamConfigVersionException):
+            ConfigProvider(section=self.parameters)(config_path, self.config_env, [self.cmd_name])
 
     def test_toml_invalid_empty_dict(self):
         config_dir = tempfile.gettempdir()
         config_path = Path(config_dir, "samconfig.toml")
         config_path.write_text("[topic]\nword=clarity\n")
 
-        self.assertEqual(self.toml_provider(config_dir, self.config_env, [self.cmd_name]), {})
+        with self.assertRaises(SamConfigFileReadException):
+            self.config_provider(config_path, self.config_env, [self.cmd_name])
 
     def test_toml_invalid_file_name(self):
         config_dir = tempfile.gettempdir()
@@ -63,16 +67,16 @@ def test_toml_invalid_file_name(self):
         config_path.write_text("version=0.1\n[config_env.topic.parameters]\nword='clarity'\n")
         config_path_invalid = Path(config_dir, "samconfig.toml")
 
-        with self.assertRaises(ConfigException):
-            self.toml_provider(config_path_invalid, self.config_env, [self.cmd_name])
+        with self.assertRaises(SamConfigFileReadException):
+            self.config_provider(config_path_invalid, self.config_env, [self.cmd_name])
 
     def test_toml_invalid_syntax(self):
         config_dir = tempfile.gettempdir()
         config_path = Path(config_dir, "samconfig.toml")
         config_path.write_text("version=0.1\n[config_env.topic.parameters]\nword=_clarity'\n")
 
-        with self.assertRaises(ConfigException):
-            self.toml_provider(config_path, self.config_env, [self.cmd_name])
+        with self.assertRaises(SamConfigFileReadException):
+            self.config_provider(config_path, self.config_env, [self.cmd_name])
 
 
 class TestCliConfiguration(TestCase):
@@ -121,6 +125,7 @@ def test_callback_with_invalid_config_file(self):
         self.ctx.parent = mock_context3
         self.ctx.info_name = "test_info"
         self.ctx.params = {"config_file": "invalid_config_file"}
+        self.ctx._parameter_source.__get__ = "COMMANDLINE"
         setattr(self.ctx, "samconfig_dir", None)
         with self.assertRaises(ConfigException):
             configuration_callback(
@@ -197,8 +202,8 @@ def test_callback_with_config_file_from_pipe(self):
         self.assertNotIn(self.value, self.saved_callback.call_args[0])
 
     def test_configuration_option(self):
-        toml_provider = TomlProvider()
-        click_option = configuration_option(provider=toml_provider)
+        config_provider = ConfigProvider()
+        click_option = configuration_option(provider=config_provider)
         clc = click_option(self.Dummy())
         self.assertEqual(clc.__click_params__[0].is_eager, True)
         self.assertEqual(
@@ -207,7 +212,7 @@ def test_configuration_option(self):
         )
         self.assertEqual(clc.__click_params__[0].hidden, True)
         self.assertEqual(clc.__click_params__[0].expose_value, False)
-        self.assertEqual(clc.__click_params__[0].callback.args, (None, None, None, toml_provider))
+        self.assertEqual(clc.__click_params__[0].callback.args, (None, None, None, config_provider))
 
     def test_get_ctx_defaults_non_nested(self):
         provider = MagicMock()
diff --git a/tests/unit/commands/delete/test_delete_context.py b/tests/unit/commands/delete/test_delete_context.py
index daa72c187b..92e2aa2c6a 100644
--- a/tests/unit/commands/delete/test_delete_context.py
+++ b/tests/unit/commands/delete/test_delete_context.py
@@ -7,7 +7,7 @@
 
 from samcli.commands.delete.delete_context import DeleteContext
 from samcli.lib.package.artifact_exporter import Template
-from samcli.cli.cli_config_file import TomlProvider
+from samcli.cli.cli_config_file import ConfigProvider
 from samcli.lib.delete.cfn_utils import CfnUtils
 from samcli.lib.package.s3_uploader import S3Uploader
 from samcli.lib.package.ecr_uploader import ECRUploader
@@ -58,7 +58,7 @@ def test_delete_context_enter(self, get_boto_client_provider_mock):
             self.assertEqual(delete_context.init_clients.call_count, 1)
 
     @patch.object(
-        TomlProvider,
+        ConfigProvider,
         "__call__",
         MagicMock(
             return_value=(
@@ -123,7 +123,7 @@ def test_delete_no_user_input(
         self.assertEqual(expected_prompt_calls, patched_prompt.call_args_list)
 
     @patch.object(
-        TomlProvider,
+        ConfigProvider,
         "__call__",
         MagicMock(
             return_value=(
@@ -506,7 +506,7 @@ def test_s3_option_flag(self):
             self.assertEqual(delete_context.s3_prefix, "s3_prefix")
 
     @patch.object(
-        TomlProvider,
+        ConfigProvider,
         "__call__",
         MagicMock(
             return_value=(
diff --git a/tests/unit/commands/samconfig/test_samconfig.py b/tests/unit/commands/samconfig/test_samconfig.py
index 675f22a4bf..b2e0822c78 100644
--- a/tests/unit/commands/samconfig/test_samconfig.py
+++ b/tests/unit/commands/samconfig/test_samconfig.py
@@ -8,7 +8,6 @@
 import tempfile
 from pathlib import Path
 from contextlib import contextmanager
-from samcli.lib.config.samconfig import SamConfig, DEFAULT_ENV
 
 from click.testing import CliRunner
 
@@ -16,6 +15,7 @@
 from unittest.mock import patch, ANY
 import logging
 
+from samcli.lib.config.samconfig import SamConfig, DEFAULT_ENV
 from samcli.lib.utils.packagetype import ZIP, IMAGE
 
 LOG = logging.getLogger()
diff --git a/tests/unit/lib/samconfig/test_file_manager.py b/tests/unit/lib/samconfig/test_file_manager.py
new file mode 100644
index 0000000000..18df66474c
--- /dev/null
+++ b/tests/unit/lib/samconfig/test_file_manager.py
@@ -0,0 +1,277 @@
+import json
+from pathlib import Path
+import tempfile
+from unittest import TestCase, skip
+
+import tomlkit
+from ruamel.yaml import YAML
+
+from samcli.lib.config.exceptions import FileParseException
+from samcli.lib.config.file_manager import COMMENT_KEY, JsonFileManager, TomlFileManager, YamlFileManager
+
+
+class TestTomlFileManager(TestCase):
+    def test_read_toml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.toml")
+        config_path.write_text(
+            "version=0.1\n[config_env.topic1.parameters]\nword='clarity'\nmultiword=['thing 1', 'thing 2']"
+        )
+        config_doc = TomlFileManager.read(config_path)
+        self.assertEqual(
+            config_doc,
+            {
+                "version": 0.1,
+                "config_env": {"topic1": {"parameters": {"word": "clarity", "multiword": ["thing 1", "thing 2"]}}},
+            },
+        )
+
+    def test_read_toml_invalid_toml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.toml")
+        config_path.write_text("fake='not real'\nimproper toml file\n")
+        with self.assertRaises(FileParseException):
+            TomlFileManager.read(config_path)
+
+    def test_read_toml_file_path_not_valid(self):
+        config_dir = "path/that/doesnt/exist"
+        config_path = Path(config_dir, "samconfig.toml")
+        config_doc = TomlFileManager.read(config_path)
+        self.assertEqual(config_doc, tomlkit.document())
+
+    def test_write_toml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.toml")
+        toml = {
+            "version": 0.1,
+            "config_env": {"topic2": {"parameters": {"word": "clarity"}}},
+            COMMENT_KEY: "This is a comment",
+        }
+
+        TomlFileManager.write(toml, config_path)
+
+        txt = config_path.read_text()
+        self.assertIn("version = 0.1", txt)
+        self.assertIn("[config_env.topic2.parameters]", txt)
+        self.assertIn('word = "clarity"', txt)
+        self.assertIn("# This is a comment", txt)
+        self.assertNotIn(COMMENT_KEY, txt)
+
+    def test_dont_write_toml_if_empty(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.toml")
+        config_path.write_text("nothing to see here\n")
+        toml = {}
+
+        TomlFileManager.write(toml, config_path)
+
+        self.assertEqual(config_path.read_text(), "nothing to see here\n")
+
+    def test_write_toml_bad_path(self):
+        config_path = Path("path/to/some", "file_that_doesnt_exist.toml")
+        with self.assertRaises(FileNotFoundError):
+            TomlFileManager.write({"key": "some value"}, config_path)
+
+    def test_write_toml_file(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.toml")
+        toml = tomlkit.parse('# This is a comment\nversion = 0.1\n[config_env.topic2.parameters]\nword = "clarity"\n')
+
+        TomlFileManager.write(toml, config_path)
+
+        txt = config_path.read_text()
+        self.assertIn("version = 0.1", txt)
+        self.assertIn("[config_env.topic2.parameters]", txt)
+        self.assertIn('word = "clarity"', txt)
+        self.assertIn("# This is a comment", txt)
+
+    def test_dont_write_toml_file_if_empty(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.toml")
+        config_path.write_text("nothing to see here\n")
+        toml = tomlkit.document()
+
+        TomlFileManager.write(toml, config_path)
+
+        self.assertEqual(config_path.read_text(), "nothing to see here\n")
+
+    def test_write_toml_file_bad_path(self):
+        config_path = Path("path/to/some", "file_that_doesnt_exist.toml")
+        with self.assertRaises(FileNotFoundError):
+            TomlFileManager.write(tomlkit.parse('key = "some value"'), config_path)
+
+    def test_toml_put_comment(self):
+        toml_doc = tomlkit.loads('version = 0.1\n[config_env.topic2.parameters]\nword = "clarity"\n')
+
+        toml_doc = TomlFileManager.put_comment(toml_doc, "This is a comment")
+
+        txt = tomlkit.dumps(toml_doc)
+        self.assertIn("# This is a comment", txt)
+
+
+class TestYamlFileManager(TestCase):
+
+    yaml = YAML()
+
+    def test_read_yaml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        config_path.write_text(
+            "version: 0.1\nconfig_env:\n  topic1:\n    parameters:\n      word: clarity\n      multiword: [thing 1, thing 2]"
+        )
+
+        config_doc = YamlFileManager.read(config_path)
+
+        self.assertEqual(
+            config_doc,
+            {
+                "version": 0.1,
+                "config_env": {"topic1": {"parameters": {"word": "clarity", "multiword": ["thing 1", "thing 2"]}}},
+            },
+        )
+
+    def test_read_yaml_invalid_yaml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        config_path.write_text("fake: not real\nthisYaml isn't correct")
+
+        with self.assertRaises(FileParseException):
+            YamlFileManager.read(config_path)
+
+    def test_read_yaml_file_path_not_valid(self):
+        config_dir = "path/that/doesnt/exist"
+        config_path = Path(config_dir, "samconfig.yaml")
+
+        config_doc = YamlFileManager.read(config_path)
+
+        self.assertEqual(config_doc, {})
+
+    def test_write_yaml(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        yaml = {
+            "version": 0.1,
+            "config_env": {"topic2": {"parameters": {"word": "clarity"}}},
+            COMMENT_KEY: "This is a comment",
+        }
+
+        YamlFileManager.write(yaml, config_path)
+
+        txt = config_path.read_text()
+        self.assertIn("version: 0.1", txt)
+        self.assertIn("config_env:\n  topic2:\n    parameters:\n", txt)
+        self.assertIn("word: clarity", txt)
+        self.assertIn("# This is a comment", txt)
+        self.assertNotIn(COMMENT_KEY, txt)
+
+    def test_dont_write_yaml_if_empty(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        config_path.write_text("nothing to see here\n")
+        yaml = {}
+
+        YamlFileManager.write(yaml, config_path)
+
+        self.assertEqual(config_path.read_text(), "nothing to see here\n")
+
+    def test_write_yaml_file_bad_path(self):
+        config_path = Path("path/to/some", "file_that_doesnt_exist.yaml")
+
+        with self.assertRaises(FileNotFoundError):
+            YamlFileManager.write(self.yaml.load("key: some value"), config_path)
+
+    def test_yaml_put_comment(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.yaml")
+        yaml_doc = self.yaml.load("version: 0.1\nconfig_env:\n  topic2:\n    parameters:\n      word: clarity\n")
+
+        yaml_doc = YamlFileManager.put_comment(yaml_doc, "This is a comment")
+
+        self.yaml.dump(yaml_doc, config_path)
+        txt = config_path.read_text()
+        self.assertIn("# This is a comment", txt)
+
+
+@skip("JSON config support disabled")
+class TestJsonFileManager(TestCase):
+    def test_read_json(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.json")
+        config_path.write_text(
+            json.dumps(
+                {
+                    "version": 0.1,
+                    "config_env": {"topic1": {"parameters": {"word": "clarity", "multiword": ["thing 1", "thing 2"]}}},
+                },
+                indent=JsonFileManager.INDENT_SIZE,
+            )
+        )
+
+        config_doc = JsonFileManager.read(config_path)
+
+        self.assertEqual(
+            config_doc,
+            {
+                "version": 0.1,
+                "config_env": {"topic1": {"parameters": {"word": "clarity", "multiword": ["thing 1", "thing 2"]}}},
+            },
+        )
+
+    def test_read_json_invalid_json(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.json")
+        config_path.write_text("{\n" + '  "bad_file": "very bad"\n' + '  "improperly": "formatted"\n' + "}\n")
+
+        with self.assertRaises(FileParseException):
+            JsonFileManager.read(config_path)
+
+    def test_read_json_file_path_not_valid(self):
+        config_dir = "path/that/doesnt/exist"
+        config_path = Path(config_dir, "samconfig.json")
+
+        config_doc = JsonFileManager.read(config_path)
+
+        self.assertEqual(config_doc, {})
+
+    def test_write_json(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.json")
+        json_doc = {
+            "version": 0.1,
+            "config_env": {"topic2": {"parameters": {"word": "clarity"}}},
+            COMMENT_KEY: "This is a comment",
+        }
+
+        JsonFileManager.write(json_doc, config_path)
+
+        txt = config_path.read_text()
+        self.assertIn('"version": 0.1', txt)
+        self.assertIn('"config_env": {', txt)
+        self.assertIn('"topic2": {', txt)
+        self.assertIn('"parameters": {', txt)
+        self.assertIn('"word": "clarity"', txt)
+        self.assertIn(f'"{COMMENT_KEY}": "This is a comment"', txt)
+
+    def test_dont_write_json_if_empty(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.json")
+        config_path.write_text("nothing to see here\n")
+        json_doc = {}
+
+        JsonFileManager.write(json_doc, config_path)
+
+        self.assertEqual(config_path.read_text(), "nothing to see here\n")
+
+    def test_write_json_file_bad_path(self):
+        config_path = Path("path/to/some", "file_that_doesnt_exist.json")
+
+        with self.assertRaises(FileNotFoundError):
+            JsonFileManager.write({"key": "value"}, config_path)
+
+    def test_json_put_comment(self):
+        json_doc = {"version": 0.1, "config_env": {"topic1": {"parameters": {"word": "clarity"}}}}
+
+        json_doc = JsonFileManager.put_comment(json_doc, "This is a comment")
+
+        txt = json.dumps(json_doc)
+        self.assertIn(f'"{COMMENT_KEY}": "This is a comment"', txt)
diff --git a/tests/unit/lib/samconfig/test_samconfig.py b/tests/unit/lib/samconfig/test_samconfig.py
index 7a86e6f97d..c58f0709a6 100644
--- a/tests/unit/lib/samconfig/test_samconfig.py
+++ b/tests/unit/lib/samconfig/test_samconfig.py
@@ -1,10 +1,21 @@
 import os
 from pathlib import Path
+from unittest.mock import patch
+from parameterized import parameterized
+import tempfile
 from unittest import TestCase
 
-from samcli.lib.config.exceptions import SamConfigVersionException
-from samcli.lib.config.samconfig import SamConfig, DEFAULT_CONFIG_FILE_NAME, DEFAULT_GLOBAL_CMDNAME, DEFAULT_ENV
+from samcli.lib.config.exceptions import SamConfigFileReadException, SamConfigVersionException
+from samcli.lib.config.file_manager import FILE_MANAGER_MAPPER, JsonFileManager, TomlFileManager, YamlFileManager
+from samcli.lib.config.samconfig import (
+    DEFAULT_CONFIG_FILE,
+    SamConfig,
+    DEFAULT_CONFIG_FILE_NAME,
+    DEFAULT_GLOBAL_CMDNAME,
+    DEFAULT_ENV,
+)
 from samcli.lib.config.version import VERSION_KEY, SAM_CONFIG_VERSION
+from samcli.lib.telemetry.event import Event
 from samcli.lib.utils import osutils
 
 
@@ -182,27 +193,27 @@ def test_check_sanity(self):
 
     def test_check_version_non_supported_type(self):
         self._setup_config()
-        self.samconfig.document.remove(VERSION_KEY)
-        self.samconfig.document.add(VERSION_KEY, "aadeff")
+        self.samconfig.document.pop(VERSION_KEY)
+        self.samconfig.document.update({VERSION_KEY: "aadeff"})
         with self.assertRaises(SamConfigVersionException):
             self.samconfig.sanity_check()
 
     def test_check_version_no_version_exists(self):
         self._setup_config()
-        self.samconfig.document.remove(VERSION_KEY)
+        self.samconfig.document.pop(VERSION_KEY)
         with self.assertRaises(SamConfigVersionException):
             self.samconfig.sanity_check()
 
     def test_check_version_float(self):
         self._setup_config()
-        self.samconfig.document.remove(VERSION_KEY)
-        self.samconfig.document.add(VERSION_KEY, 0.2)
+        self.samconfig.document.pop(VERSION_KEY)
+        self.samconfig.document.update({VERSION_KEY: 0.2})
         self.samconfig.sanity_check()
 
     def test_write_config_file_non_standard_version(self):
         self._setup_config()
-        self.samconfig.document.remove(VERSION_KEY)
-        self.samconfig.document.add(VERSION_KEY, 0.2)
+        self.samconfig.document.pop(VERSION_KEY)
+        self.samconfig.document.update({VERSION_KEY: 0.2})
         self.samconfig.put(cmd_names=["local", "start", "api"], section="parameters", key="skip_pull_image", value=True)
         self.samconfig.sanity_check()
         self.assertEqual(self.samconfig.document.get(VERSION_KEY), 0.2)
@@ -210,7 +221,7 @@ def test_write_config_file_non_standard_version(self):
     def test_write_config_file_will_create_the_file_if_not_exist(self):
         with osutils.mkdir_temp(ignore_errors=True) as tempdir:
             non_existing_dir = os.path.join(tempdir, "non-existing-dir")
-            non_existing_file = "non-existing-file"
+            non_existing_file = "non-existing-file.toml"
             samconfig = SamConfig(config_dir=non_existing_dir, filename=non_existing_file)
 
             self.assertFalse(samconfig.exists())
@@ -221,3 +232,84 @@ def test_write_config_file_will_create_the_file_if_not_exist(self):
             samconfig.put(cmd_names=["any", "command"], section="any-section", key="any-key", value="any-value")
             samconfig.flush()
             self.assertTrue(samconfig.exists())
+
+    def test_passed_filename_used(self):
+        config_path = Path(self.config_dir, "myconfigfile.toml")
+
+        self.assertFalse(config_path.exists())
+
+        self.samconfig = SamConfig(self.config_dir, filename="myconfigfile.toml")
+        self.samconfig.put(  # put some config options so it creates the file
+            cmd_names=["any", "command"], section="section", key="key", value="value"
+        )
+        self.samconfig.flush()
+
+        self.assertTrue(config_path.exists())
+        self.assertFalse(Path(self.config_dir, DEFAULT_CONFIG_FILE_NAME).exists())
+
+    def test_config_uses_default_if_none_provided(self):
+        self.samconfig = SamConfig(self.config_dir)
+        self.samconfig.put(  # put some config options so it creates the file
+            cmd_names=["any", "command"], section="section", key="key", value="value"
+        )
+        self.samconfig.flush()
+
+        self.assertTrue(Path(self.config_dir, DEFAULT_CONFIG_FILE_NAME).exists())
+
+    def test_config_priority(self):
+        config_files = []
+        extensions_in_priority = list(FILE_MANAGER_MAPPER.keys())  # priority by order in dict
+        for extension in extensions_in_priority:
+            filename = DEFAULT_CONFIG_FILE + extension
+            config = SamConfig(self.config_dir, filename=filename)
+            config.put(  # put some config options so it creates the file
+                cmd_names=["any", "command"], section="section", key="key", value="value"
+            )
+            config.flush()
+            config_files.append(config)
+
+        while extensions_in_priority:
+            config = SamConfig(self.config_dir)
+            next_priority = extensions_in_priority.pop(0)
+            self.assertEqual(config.filepath, Path(self.config_dir, DEFAULT_CONFIG_FILE + next_priority))
+            os.remove(config.path())
+
+
+class TestSamConfigFileManager(TestCase):
+    def test_file_manager_not_declared(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig")
+
+        with self.assertRaises(SamConfigFileReadException):
+            SamConfig(config_path, filename="samconfig")
+
+    def test_file_manager_unsupported(self):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, "samconfig.jpeg")
+
+        with self.assertRaises(SamConfigFileReadException):
+            SamConfig(config_path, filename="samconfig.jpeg")
+
+    @parameterized.expand(
+        [
+            ("samconfig.toml", TomlFileManager, ".toml"),
+            ("samconfig.yaml", YamlFileManager, ".yaml"),
+            ("samconfig.yml", YamlFileManager, ".yml"),
+            # ("samconfig.json", JsonFileManager, ".json"),
+        ]
+    )
+    @patch("samcli.lib.telemetry.event.EventTracker.track_event")
+    def test_file_manager(self, filename, expected_file_manager, expected_extension, track_mock):
+        config_dir = tempfile.gettempdir()
+        config_path = Path(config_dir, filename)
+        tracked_events = []
+
+        def mock_tracker(name, value):  # when track_event is called, just append the Event to our list
+            tracked_events.append(Event(name, value))
+
+        track_mock.side_effect = mock_tracker
+
+        samconfig = SamConfig(config_path, filename=filename)
+
+        self.assertIs(samconfig.file_manager, expected_file_manager)
+        self.assertIn(Event("SamConfigFileExtension", expected_extension), tracked_events)