diff --git a/app_dart/integration_test/validate_all_ci_configs_test.dart b/app_dart/integration_test/validate_all_ci_configs_test.dart
index 194cec175e..111eb5f869 100644
--- a/app_dart/integration_test/validate_all_ci_configs_test.dart
+++ b/app_dart/integration_test/validate_all_ci_configs_test.dart
@@ -4,6 +4,7 @@
 
 import 'dart:io' as io;
 
+import 'package:cocoon_scheduler/scheduler.dart';
 import 'package:cocoon_service/cocoon_service.dart';
 import 'package:test/test.dart';
 import 'package:yaml/yaml.dart';
diff --git a/app_dart/lib/src/model/appengine/task.dart b/app_dart/lib/src/model/appengine/task.dart
index 5306c97334..104fee0758 100644
--- a/app_dart/lib/src/model/appengine/task.dart
+++ b/app_dart/lib/src/model/appengine/task.dart
@@ -2,12 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:cocoon_scheduler/scheduler.dart' as pb;
 import 'package:gcloud/db.dart';
 import 'package:json_annotation/json_annotation.dart';
 import 'package:meta/meta.dart';
 
 import '../../service/luci.dart';
-import '../proto/internal/scheduler.pb.dart' as pb;
 import 'commit.dart';
 import 'key_converter.dart';
 
diff --git a/app_dart/lib/src/model/proto/protos.dart b/app_dart/lib/src/model/proto/protos.dart
index e62728bfa6..3e25c58606 100644
--- a/app_dart/lib/src/model/proto/protos.dart
+++ b/app_dart/lib/src/model/proto/protos.dart
@@ -6,6 +6,5 @@ export 'internal/build_status_response.pb.dart';
 export 'internal/commit.pb.dart';
 export 'internal/commit_status.pb.dart';
 export 'internal/key.pb.dart';
-export 'internal/scheduler.pb.dart';
 export 'internal/stage.pb.dart';
 export 'internal/task.pb.dart';
diff --git a/app_dart/lib/src/service/luci.dart b/app_dart/lib/src/service/luci.dart
index 429c436d73..54c83fa95f 100644
--- a/app_dart/lib/src/service/luci.dart
+++ b/app_dart/lib/src/service/luci.dart
@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:math';
 
 import 'package:appengine/appengine.dart';
+import 'package:cocoon_scheduler/scheduler.dart';
 import 'package:github/github.dart';
 import 'package:json_annotation/json_annotation.dart';
 import 'package:meta/meta.dart';
@@ -13,7 +14,6 @@ import 'package:retry/retry.dart';
 
 import '../model/appengine/task.dart';
 import '../model/luci/buildbucket.dart';
-import '../model/proto/internal/scheduler.pb.dart';
 import '../request_handling/api_request_handler.dart';
 import 'buildbucket.dart';
 import 'config.dart';
diff --git a/app_dart/lib/src/service/scheduler.dart b/app_dart/lib/src/service/scheduler.dart
index b2a3613f96..76e8940901 100644
--- a/app_dart/lib/src/service/scheduler.dart
+++ b/app_dart/lib/src/service/scheduler.dart
@@ -6,7 +6,7 @@ import 'dart:io';
 import 'dart:typed_data';
 
 import 'package:appengine/appengine.dart';
-import 'package:cocoon_service/src/model/luci/buildbucket.dart';
+import 'package:cocoon_scheduler/scheduler.dart';
 import 'package:gcloud/db.dart';
 import 'package:github/github.dart' as github;
 import 'package:googleapis/bigquery/v2.dart';
@@ -21,7 +21,7 @@ import '../foundation/utils.dart';
 import '../model/appengine/commit.dart';
 import '../model/appengine/task.dart';
 import '../model/github/checks.dart';
-import '../model/proto/protos.dart' show SchedulerConfig, Target;
+import '../model/luci/buildbucket.dart';
 import '../request_handling/exceptions.dart';
 import 'cache_service.dart';
 import 'config.dart';
@@ -434,57 +434,3 @@ class Scheduler {
     }
   }
 }
-
-/// Load [yamlConfig] to [SchedulerConfig] and validate the dependency graph.
-SchedulerConfig schedulerConfigFromYaml(YamlMap yamlConfig) {
-  final SchedulerConfig config = SchedulerConfig();
-  config.mergeFromProto3Json(yamlConfig);
-  _validateSchedulerConfig(config);
-
-  return config;
-}
-
-void _validateSchedulerConfig(SchedulerConfig schedulerConfig) {
-  if (schedulerConfig.targets.isEmpty) {
-    throw const FormatException('Scheduler config must have at least 1 target');
-  }
-
-  if (schedulerConfig.enabledBranches.isEmpty) {
-    throw const FormatException('Scheduler config must have at least 1 enabled branch');
-  }
-
-  final Map<String, List<Target>> targetGraph = <String, List<Target>>{};
-  final List<String> exceptions = <String>[];
-  // Construct [targetGraph]. With a one scan approach, cycles in the graph
-  // cannot exist as it only works forward.
-  for (final Target target in schedulerConfig.targets) {
-    if (targetGraph.containsKey(target.name)) {
-      exceptions.add('ERROR: ${target.name} already exists in graph');
-    } else {
-      targetGraph[target.name] = <Target>[];
-      // Add edges
-      if (target.dependencies.isNotEmpty) {
-        if (target.dependencies.length != 1) {
-          exceptions
-              .add('ERROR: ${target.name} has multiple dependencies which is not supported. Use only one dependency');
-        } else {
-          if (target.dependencies.first == target.name) {
-            exceptions.add('ERROR: ${target.name} cannot depend on itself');
-          } else if (targetGraph.containsKey(target.dependencies.first)) {
-            targetGraph[target.dependencies.first].add(target);
-          } else {
-            exceptions.add('ERROR: ${target.name} depends on ${target.dependencies.first} which does not exist');
-          }
-        }
-      }
-    }
-  }
-  _checkExceptions(exceptions);
-}
-
-void _checkExceptions(List<String> exceptions) {
-  if (exceptions.isNotEmpty) {
-    final String fullException = exceptions.reduce((String exception, _) => exception + '\n');
-    throw FormatException(fullException);
-  }
-}
diff --git a/app_dart/pubspec.lock b/app_dart/pubspec.lock
index ce459dc6ac..56474d752b 100644
--- a/app_dart/pubspec.lock
+++ b/app_dart/pubspec.lock
@@ -141,6 +141,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.1"
+  cocoon_scheduler:
+    dependency: "direct main"
+    description:
+      path: "../scheduler"
+      relative: true
+    source: path
+    version: "1.0.0"
   code_builder:
     dependency: transitive
     description:
@@ -695,7 +702,7 @@ packages:
     source: hosted
     version: "0.0.5"
   yaml:
-    dependency: "direct main"
+    dependency: transitive
     description:
       name: yaml
       url: "https://pub.dartlang.org"
diff --git a/app_dart/pubspec.yaml b/app_dart/pubspec.yaml
index 2914d106ae..645724d191 100644
--- a/app_dart/pubspec.yaml
+++ b/app_dart/pubspec.yaml
@@ -12,6 +12,8 @@ environment:
 
 dependencies:
   appengine: ^0.11.0
+  cocoon_scheduler:
+    path: ../scheduler
   collection: ^1.14.11
   corsac_jwt: ^0.2.2
   crypto: ^2.0.6
@@ -31,7 +33,6 @@ dependencies:
   neat_cache: ^1.0.1
   protobuf: ^1.0.0
   truncate: ^2.1.2
-  yaml: ^2.1.16
 
 dev_dependencies:
   build_runner: ^1.0.0
diff --git a/app_dart/test/service/scheduler_test.dart b/app_dart/test/service/scheduler_test.dart
index 182992f61a..08fd788c18 100644
--- a/app_dart/test/service/scheduler_test.dart
+++ b/app_dart/test/service/scheduler_test.dart
@@ -4,7 +4,6 @@
 
 import 'dart:convert';
 
-import 'package:cocoon_service/protos.dart' show SchedulerConfig, SchedulerSystem, Target;
 import 'package:cocoon_service/src/model/appengine/commit.dart';
 import 'package:cocoon_service/src/model/appengine/task.dart';
 import 'package:cocoon_service/src/model/github/checks.dart' as cocoon_github;
@@ -20,7 +19,6 @@ import 'package:github/github.dart';
 import 'package:googleapis/bigquery/v2.dart';
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
-import 'package:yaml/yaml.dart';
 
 import '../model/github/checks_test_data.dart';
 import '../src/datastore/fake_config.dart';
@@ -382,179 +380,6 @@ targets:
         expect(retryRequest.builderId.builder, 'Linux A');
       });
     });
-
-    group('scheduler config', () {
-      test('constructs graph with one target', () {
-        final YamlMap singleTargetConfig = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-    builder: builderA
-    properties:
-      test: abc
-      ''') as YamlMap;
-        final SchedulerConfig schedulerConfig = schedulerConfigFromYaml(singleTargetConfig);
-        expect(schedulerConfig.enabledBranches, <String>['master']);
-        expect(schedulerConfig.targets.length, 1);
-        final Target target = schedulerConfig.targets.first;
-        expect(target.bringup, false);
-        expect(target.name, 'A');
-        expect(target.properties, <String, String>{
-          'test': 'abc',
-        });
-        expect(target.builder, 'builderA');
-        expect(target.scheduler, SchedulerSystem.cocoon);
-        expect(target.testbed, 'linux-vm');
-        expect(target.timeout, 30);
-      });
-
-      test('throws exception when non-existent scheduler is given', () {
-        final YamlMap targetWithNonexistentScheduler = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-    scheduler: dashatar
-      ''') as YamlMap;
-        expect(() => schedulerConfigFromYaml(targetWithNonexistentScheduler), throwsA(isA<FormatException>()));
-      });
-
-      test('constructs graph with dependency chain', () {
-        final YamlMap dependentTargetConfig = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-  - name: B
-    dependencies:
-      - A
-  - name: C
-    dependencies:
-      - B
-      ''') as YamlMap;
-        final SchedulerConfig schedulerConfig = schedulerConfigFromYaml(dependentTargetConfig);
-        expect(schedulerConfig.targets.length, 3);
-        final Target a = schedulerConfig.targets.first;
-        final Target b = schedulerConfig.targets[1];
-        final Target c = schedulerConfig.targets[2];
-        expect(a.name, 'A');
-        expect(b.name, 'B');
-        expect(b.dependencies, <String>['A']);
-        expect(c.name, 'C');
-        expect(c.dependencies, <String>['B']);
-      });
-
-      test('constructs graph with parent with two dependents', () {
-        final YamlMap twoDependentTargetConfig = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-  - name: B1
-    dependencies:
-      - A
-  - name: B2
-    dependencies:
-      - A
-      ''') as YamlMap;
-        final SchedulerConfig schedulerConfig = schedulerConfigFromYaml(twoDependentTargetConfig);
-        expect(schedulerConfig.targets.length, 3);
-        final Target a = schedulerConfig.targets.first;
-        final Target b1 = schedulerConfig.targets[1];
-        final Target b2 = schedulerConfig.targets[2];
-        expect(a.name, 'A');
-        expect(b1.name, 'B1');
-        expect(b1.dependencies, <String>['A']);
-        expect(b2.name, 'B2');
-        expect(b2.dependencies, <String>['A']);
-      });
-
-      test('fails when there are cyclic targets', () {
-        final YamlMap configWithCycle = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-    dependencies:
-      - B
-  - name: B
-    dependencies:
-      - A
-      ''') as YamlMap;
-        expect(
-            () => schedulerConfigFromYaml(configWithCycle),
-            throwsA(
-              isA<FormatException>().having(
-                (FormatException e) => e.toString(),
-                'message',
-                contains('ERROR: A depends on B which does not exist'),
-              ),
-            ));
-      });
-
-      test('fails when there are duplicate targets', () {
-        final YamlMap configWithDuplicateTargets = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-  - name: A
-      ''') as YamlMap;
-        expect(
-            () => schedulerConfigFromYaml(configWithDuplicateTargets),
-            throwsA(
-              isA<FormatException>().having(
-                (FormatException e) => e.toString(),
-                'message',
-                contains('ERROR: A already exists in graph'),
-              ),
-            ));
-      });
-
-      test('fails when there are multiple dependencies', () {
-        final YamlMap configWithMultipleDependencies = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-  - name: B
-  - name: C
-    dependencies:
-      - A
-      - B
-      ''') as YamlMap;
-        expect(
-            () => schedulerConfigFromYaml(configWithMultipleDependencies),
-            throwsA(
-              isA<FormatException>().having(
-                (FormatException e) => e.toString(),
-                'message',
-                contains('ERROR: C has multiple dependencies which is not supported. Use only one dependency'),
-              ),
-            ));
-      });
-
-      test('fails when dependency does not exist', () {
-        final YamlMap configWithMissingTarget = loadYaml('''
-enabled_branches:
-  - master
-targets:
-  - name: A
-    dependencies:
-      - B
-      ''') as YamlMap;
-        expect(
-            () => schedulerConfigFromYaml(configWithMissingTarget),
-            throwsA(
-              isA<FormatException>().having(
-                (FormatException e) => e.toString(),
-                'message',
-                contains('ERROR: A depends on B which does not exist'),
-              ),
-            ));
-      });
-    });
   });
 }
 
diff --git a/app_dart/test/src/service/fake_scheduler.dart b/app_dart/test/src/service/fake_scheduler.dart
index bbd3966266..0e84771e43 100644
--- a/app_dart/test/src/service/fake_scheduler.dart
+++ b/app_dart/test/src/service/fake_scheduler.dart
@@ -2,9 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:cocoon_scheduler/models/scheduler.pb.dart';
 import 'package:cocoon_service/src/foundation/github_checks_util.dart';
 import 'package:cocoon_service/src/model/appengine/commit.dart';
-import 'package:cocoon_service/src/model/proto/internal/scheduler.pb.dart';
 import 'package:cocoon_service/src/service/buildbucket.dart';
 import 'package:cocoon_service/src/service/cache_service.dart';
 import 'package:cocoon_service/src/service/config.dart';
diff --git a/scheduler/.gitignore b/scheduler/.gitignore
new file mode 100644
index 0000000000..3c8a157278
--- /dev/null
+++ b/scheduler/.gitignore
@@ -0,0 +1,6 @@
+# Files and directories created by pub.
+.dart_tool/
+.packages
+
+# Conventional directory for build output.
+build/
diff --git a/scheduler/CHANGELOG.md b/scheduler/CHANGELOG.md
new file mode 100644
index 0000000000..effe43c82c
--- /dev/null
+++ b/scheduler/CHANGELOG.md
@@ -0,0 +1,3 @@
+## 1.0.0
+
+- Initial version.
diff --git a/scheduler/README.md b/scheduler/README.md
new file mode 100644
index 0000000000..c290132dc8
--- /dev/null
+++ b/scheduler/README.md
@@ -0,0 +1,3 @@
+# Scheduler
+
+Logic for Flutter infrastructure tasks being scheduled on physical devices.
\ No newline at end of file
diff --git a/scheduler/analysis_options.yaml b/scheduler/analysis_options.yaml
new file mode 100644
index 0000000000..804c2c61f0
--- /dev/null
+++ b/scheduler/analysis_options.yaml
@@ -0,0 +1,194 @@
+# Specify analysis options.
+#
+# Until there are meta linter rules, each desired lint must be explicitly enabled.
+# See: https://github.com/dart-lang/linter/issues/288
+#
+# For a list of lints, see: http://dart-lang.github.io/linter/lints/
+# See the configuration guide for more
+# https://github.com/dart-lang/sdk/tree/master/pkg/analyzer#configuring-the-analyzer
+#
+# There are other similar analysis options files in the flutter repos,
+# which should be kept in sync with this file:
+#
+#   - analysis_options.yaml (this file)
+#   - packages/flutter/lib/analysis_options_user.yaml
+#   - https://github.com/flutter/plugins/blob/master/analysis_options.yaml
+#   - https://github.com/flutter/engine/blob/master/analysis_options.yaml
+#
+# This file contains the analysis options used by Flutter tools, such as IntelliJ,
+# Android Studio, and the `flutter analyze` command.
+
+analyzer:
+  strong-mode:
+    implicit-casts: false
+    implicit-dynamic: false
+  errors:
+    # treat missing required parameters as a warning (not a hint)
+    missing_required_param: warning
+    # treat missing returns as a warning (not a hint)
+    missing_return: warning
+    # allow having TODOs in the code
+    todo: ignore
+    # Ignore analyzer hints for updating pubspecs when using Future or
+    # Stream and not importing dart:async
+    # Please see https://github.com/flutter/flutter/pull/24528 for details.
+    sdk_version_async_exported_from_core: ignore
+    implicit_dynamic_parameter: info
+  exclude:
+    - ".dart_tool/**"
+    - "**/*.g.dart"
+    - "**/*.pb.dart"
+    - "**/*.pbjson.dart"
+    - "**/*.pbenum.dart"
+
+linter:
+  rules:
+    # these rules are documented on and in the same order as
+    # the Dart Lint rules page to make maintenance easier
+    # https://github.com/dart-lang/linter/blob/master/example/all.yaml
+    - always_declare_return_types
+    - always_put_control_body_on_new_line
+    # - always_put_required_named_parameters_first # we prefer having parameters in the same order as fields https://github.com/flutter/flutter/issues/10219
+    - always_require_non_null_named_parameters
+    - always_specify_types
+    - annotate_overrides
+    # - avoid_annotating_with_dynamic # conflicts with always_specify_types
+    # - avoid_as # incompatible with implicit-casts: false
+    - avoid_bool_literals_in_conditional_expressions
+    # - avoid_catches_without_on_clauses # we do this commonly
+    # - avoid_catching_errors # we do this commonly
+    - avoid_classes_with_only_static_members
+    # - avoid_double_and_int_checks # only useful when targeting JS runtime
+    - avoid_empty_else
+    - avoid_field_initializers_in_const_classes
+    - avoid_function_literals_in_foreach_calls
+    # - avoid_implementing_value_types # not yet tested
+    - avoid_init_to_null
+    # - avoid_js_rounded_ints # only useful when targeting JS runtime
+    - avoid_null_checks_in_equality_operators
+    # - avoid_positional_boolean_parameters # not yet tested
+    # - avoid_private_typedef_functions # we prefer having typedef (discussion in https://github.com/flutter/flutter/pull/16356)
+    - avoid_relative_lib_imports
+    - avoid_renaming_method_parameters
+    - avoid_return_types_on_setters
+    # - avoid_returning_null # there are plenty of valid reasons to return null
+    # - avoid_returning_null_for_future # not yet tested
+    - avoid_returning_null_for_void
+    # - avoid_returning_this # there are plenty of valid reasons to return this
+    # - avoid_setters_without_getters # not yet tested
+    # - avoid_shadowing_type_parameters # not yet tested
+    # - avoid_single_cascade_in_expression_statements # not yet tested
+    - avoid_slow_async_io
+    - avoid_types_as_parameter_names
+    # - avoid_types_on_closure_parameters # conflicts with always_specify_types
+    - avoid_unused_constructor_parameters
+    - avoid_void_async
+    - await_only_futures
+    - camel_case_types
+    - cancel_subscriptions
+    # - cascade_invocations # not yet tested
+    # - close_sinks # not reliable enough
+    # - comment_references # blocked on https://github.com/flutter/flutter/issues/20765
+    # - constant_identifier_names # needs an opt-out https://github.com/dart-lang/linter/issues/204
+    - control_flow_in_finally
+    - curly_braces_in_flow_control_structures
+    # - diagnostic_describe_all_properties # not yet tested
+    - directives_ordering
+    - empty_catches
+    - empty_constructor_bodies
+    - empty_statements
+    # - file_names # not yet tested
+    - flutter_style_todos
+    - hash_and_equals
+    - implementation_imports
+    # - invariant_booleans # too many false positives: https://github.com/dart-lang/linter/issues/811
+    - iterable_contains_unrelated_type
+    # - join_return_with_assignment # not yet tested
+    - library_names
+    - library_prefixes
+    # - lines_longer_than_80_chars # not yet tested
+    - list_remove_unrelated_type
+    # - literal_only_boolean_expressions # too many false positives: https://github.com/dart-lang/sdk/issues/34181
+    - no_adjacent_strings_in_list
+    - no_duplicate_case_values
+    - non_constant_identifier_names
+    # - null_closures  # not yet tested
+    # - omit_local_variable_types # opposite of always_specify_types
+    # - one_member_abstracts # too many false positives
+    # - only_throw_errors # https://github.com/flutter/flutter/issues/5792
+    - overridden_fields
+    - package_api_docs
+    - package_names
+    - package_prefixed_library_names
+    # - parameter_assignments # we do this commonly
+    - prefer_adjacent_string_concatenation
+    - prefer_asserts_in_initializer_lists
+    # - prefer_asserts_with_message # not yet tested
+    - prefer_collection_literals
+    - prefer_conditional_assignment
+    - prefer_const_constructors
+    - prefer_const_constructors_in_immutables
+    - prefer_const_declarations
+    - prefer_const_literals_to_create_immutables
+    # - prefer_constructors_over_static_methods # not yet tested
+    - prefer_contains
+    # - prefer_double_quotes # opposite of prefer_single_quotes
+    - prefer_equal_for_default_values
+    # - prefer_expression_function_bodies # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#consider-using--for-short-functions-and-methods
+    - prefer_final_fields
+    # - prefer_final_in_for_each # not yet tested
+    - prefer_final_locals
+    # - prefer_for_elements_to_map_fromIterable # not yet tested
+    - prefer_foreach
+    # - prefer_function_declarations_over_variables # not yet tested
+    - prefer_generic_function_type_aliases
+    # - prefer_if_elements_to_conditional_expressions # not yet tested
+    - prefer_if_null_operators
+    - prefer_initializing_formals
+    - prefer_inlined_adds
+    # - prefer_int_literals # not yet tested
+    # - prefer_interpolation_to_compose_strings # not yet tested
+    - prefer_is_empty
+    - prefer_is_not_empty
+    - prefer_iterable_whereType
+    # - prefer_mixin # https://github.com/dart-lang/language/issues/32
+    # - prefer_null_aware_operators # disable until NNBD, see https://github.com/flutter/flutter/pull/32711#issuecomment-492930932
+    - prefer_single_quotes
+    - prefer_spread_collections
+    - prefer_typing_uninitialized_variables
+    - prefer_void_to_null
+    # - provide_deprecation_message # not yet tested
+    # - public_member_api_docs # enabled on a case-by-case basis; see e.g. packages/analysis_options.yaml
+    - recursive_getters
+    - slash_for_doc_comments
+    # - sort_child_properties_last # not yet tested
+    - sort_constructors_first
+    - sort_pub_dependencies
+    - sort_unnamed_constructors_first
+    - test_types_in_equals
+    - throw_in_finally
+    # - type_annotate_public_apis # subset of always_specify_types
+    - type_init_formals
+    - unawaited_futures
+    # - unnecessary_await_in_return # not yet tested
+    - unnecessary_brace_in_string_interps
+    - unnecessary_const
+    - unnecessary_getters_setters
+    # - unnecessary_lambdas # has false positives: https://github.com/dart-lang/linter/issues/498
+    - unnecessary_new
+    - unnecessary_null_aware_assignments
+    - unnecessary_null_in_if_null_operators
+    - unnecessary_overrides
+    - unnecessary_parenthesis
+    - unnecessary_statements
+    - unnecessary_this
+    - unrelated_type_equality_checks
+    # - unsafe_html # not yet tested
+    - use_full_hex_values_for_flutter_colors
+    # - use_function_type_syntax_for_parameters # not yet tested
+    - use_rethrow_when_possible
+    # - use_setters_to_change_properties # not yet tested
+    # - use_string_buffers # has false positives: https://github.com/dart-lang/sdk/issues/34182
+    # - use_to_and_as_if_applicable # has false positives, so we prefer to catch this by code-review
+    - valid_regexps
+    # - void_checks # not yet tested
diff --git a/app_dart/bin/validate_scheduler_config.dart b/scheduler/bin/validate_scheduler_config.dart
similarity index 84%
rename from app_dart/bin/validate_scheduler_config.dart
rename to scheduler/bin/validate_scheduler_config.dart
index 97fd5e0c74..1765229c0d 100644
--- a/app_dart/bin/validate_scheduler_config.dart
+++ b/scheduler/bin/validate_scheduler_config.dart
@@ -4,7 +4,8 @@
 
 import 'dart:io';
 
-import 'package:cocoon_service/cocoon_service.dart';
+import 'package:cocoon_scheduler/scheduler.dart';
+// ignore: import_of_legacy_library_into_null_safe
 import 'package:yaml/yaml.dart';
 
 void main(List<String> args) {
diff --git a/app_dart/lib/src/model/proto/internal/scheduler.pb.dart b/scheduler/lib/models/scheduler.pb.dart
similarity index 100%
rename from app_dart/lib/src/model/proto/internal/scheduler.pb.dart
rename to scheduler/lib/models/scheduler.pb.dart
diff --git a/app_dart/lib/src/model/proto/internal/scheduler.pbenum.dart b/scheduler/lib/models/scheduler.pbenum.dart
similarity index 100%
rename from app_dart/lib/src/model/proto/internal/scheduler.pbenum.dart
rename to scheduler/lib/models/scheduler.pbenum.dart
diff --git a/app_dart/lib/src/model/proto/internal/scheduler.pbjson.dart b/scheduler/lib/models/scheduler.pbjson.dart
similarity index 100%
rename from app_dart/lib/src/model/proto/internal/scheduler.pbjson.dart
rename to scheduler/lib/models/scheduler.pbjson.dart
diff --git a/app_dart/lib/src/model/proto/internal/scheduler.proto b/scheduler/lib/models/scheduler.proto
similarity index 100%
rename from app_dart/lib/src/model/proto/internal/scheduler.proto
rename to scheduler/lib/models/scheduler.proto
diff --git a/scheduler/lib/scheduler.dart b/scheduler/lib/scheduler.dart
new file mode 100644
index 0000000000..e72c7d2414
--- /dev/null
+++ b/scheduler/lib/scheduler.dart
@@ -0,0 +1,62 @@
+// Copyright 2021 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:yaml/yaml.dart';
+import 'models/scheduler.pb.dart';
+
+export 'models/scheduler.pb.dart';
+
+/// Load [yamlConfig] to [SchedulerConfig] and validate the dependency graph.
+SchedulerConfig schedulerConfigFromYaml(YamlMap yamlConfig) {
+  final SchedulerConfig config = SchedulerConfig();
+  config.mergeFromProto3Json(yamlConfig);
+  _validateSchedulerConfig(config);
+
+  return config;
+}
+
+void _validateSchedulerConfig(SchedulerConfig schedulerConfig) {
+  if (schedulerConfig.targets.isEmpty) {
+    throw const FormatException('Scheduler config must have at least 1 target');
+  }
+
+  if (schedulerConfig.enabledBranches.isEmpty) {
+    throw const FormatException('Scheduler config must have at least 1 enabled branch');
+  }
+
+  final Map<String, List<Target>> targetGraph = <String, List<Target>>{};
+  final List<String> exceptions = <String>[];
+  // Construct [targetGraph]. With a one scan approach, cycles in the graph
+  // cannot exist as it only works forward.
+  for (final Target target in schedulerConfig.targets) {
+    if (targetGraph.containsKey(target.name)) {
+      exceptions.add('ERROR: ${target.name} already exists in graph');
+    } else {
+      targetGraph[target.name] = <Target>[];
+      // Add edges
+      if (target.dependencies.isNotEmpty) {
+        if (target.dependencies.length != 1) {
+          exceptions
+              .add('ERROR: ${target.name} has multiple dependencies which is not supported. Use only one dependency');
+        } else {
+          if (target.dependencies.first == target.name) {
+            exceptions.add('ERROR: ${target.name} cannot depend on itself');
+          } else if (targetGraph.containsKey(target.dependencies.first)) {
+            targetGraph[target.dependencies.first].add(target);
+          } else {
+            exceptions.add('ERROR: ${target.name} depends on ${target.dependencies.first} which does not exist');
+          }
+        }
+      }
+    }
+  }
+  _checkExceptions(exceptions);
+}
+
+void _checkExceptions(List<String> exceptions) {
+  if (exceptions.isNotEmpty) {
+    final String fullException = exceptions.reduce((String exception, _) => exception + '\n');
+    throw FormatException(fullException);
+  }
+}
diff --git a/scheduler/pubspec.lock b/scheduler/pubspec.lock
new file mode 100644
index 0000000000..120a68528c
--- /dev/null
+++ b/scheduler/pubspec.lock
@@ -0,0 +1,348 @@
+# Generated by pub
+# See https://dart.dev/tools/pub/glossary#lockfile
+packages:
+  _fe_analyzer_shared:
+    dependency: transitive
+    description:
+      name: _fe_analyzer_shared
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "14.0.0"
+  analyzer:
+    dependency: transitive
+    description:
+      name: analyzer
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.41.2"
+  args:
+    dependency: transitive
+    description:
+      name: args
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0"
+  async:
+    dependency: transitive
+    description:
+      name: async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.6.1"
+  boolean_selector:
+    dependency: transitive
+    description:
+      name: boolean_selector
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0"
+  charcode:
+    dependency: transitive
+    description:
+      name: charcode
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0"
+  cli_util:
+    dependency: transitive
+    description:
+      name: cli_util
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.3.0"
+  collection:
+    dependency: transitive
+    description:
+      name: collection
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.15.0"
+  convert:
+    dependency: transitive
+    description:
+      name: convert
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.0"
+  coverage:
+    dependency: transitive
+    description:
+      name: coverage
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.15.2"
+  crypto:
+    dependency: transitive
+    description:
+      name: crypto
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.1"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "6.1.0"
+  fixnum:
+    dependency: transitive
+    description:
+      name: fixnum
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.10.11"
+  glob:
+    dependency: transitive
+    description:
+      name: glob
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
+  http_multi_server:
+    dependency: transitive
+    description:
+      name: http_multi_server
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.1"
+  http_parser:
+    dependency: transitive
+    description:
+      name: http_parser
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "4.0.0"
+  io:
+    dependency: transitive
+    description:
+      name: io
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.6.3"
+  logging:
+    dependency: transitive
+    description:
+      name: logging
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
+  matcher:
+    dependency: transitive
+    description:
+      name: matcher
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.12.10"
+  meta:
+    dependency: transitive
+    description:
+      name: meta
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.3.0"
+  mime:
+    dependency: transitive
+    description:
+      name: mime
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
+  node_preamble:
+    dependency: transitive
+    description:
+      name: node_preamble
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.4.13"
+  package_config:
+    dependency: transitive
+    description:
+      name: package_config
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.9.3"
+  path:
+    dependency: transitive
+    description:
+      name: path
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.8.0"
+  pedantic:
+    dependency: "direct dev"
+    description:
+      name: pedantic
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.11.0"
+  pool:
+    dependency: transitive
+    description:
+      name: pool
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.5.0"
+  protobuf:
+    dependency: "direct main"
+    description:
+      name: protobuf
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.3"
+  pub_semver:
+    dependency: transitive
+    description:
+      name: pub_semver
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  shelf:
+    dependency: transitive
+    description:
+      name: shelf
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.2"
+  shelf_packages_handler:
+    dependency: transitive
+    description:
+      name: shelf_packages_handler
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.0"
+  shelf_static:
+    dependency: transitive
+    description:
+      name: shelf_static
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
+  shelf_web_socket:
+    dependency: transitive
+    description:
+      name: shelf_web_socket
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
+  source_map_stack_trace:
+    dependency: transitive
+    description:
+      name: source_map_stack_trace
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0"
+  source_maps:
+    dependency: transitive
+    description:
+      name: source_maps
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.10.10"
+  source_span:
+    dependency: transitive
+    description:
+      name: source_span
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.8.1"
+  stack_trace:
+    dependency: transitive
+    description:
+      name: stack_trace
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.10.0"
+  stream_channel:
+    dependency: transitive
+    description:
+      name: stream_channel
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0"
+  string_scanner:
+    dependency: transitive
+    description:
+      name: string_scanner
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0"
+  term_glyph:
+    dependency: transitive
+    description:
+      name: term_glyph
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0"
+  test:
+    dependency: "direct dev"
+    description:
+      name: test
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.16.5"
+  test_api:
+    dependency: transitive
+    description:
+      name: test_api
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.2.19"
+  test_core:
+    dependency: transitive
+    description:
+      name: test_core
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.3.15"
+  typed_data:
+    dependency: transitive
+    description:
+      name: typed_data
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.3.0"
+  vm_service:
+    dependency: transitive
+    description:
+      name: vm_service
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "6.2.0"
+  watcher:
+    dependency: transitive
+    description:
+      name: watcher
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
+  web_socket_channel:
+    dependency: transitive
+    description:
+      name: web_socket_channel
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0"
+  webkit_inspection_protocol:
+    dependency: transitive
+    description:
+      name: webkit_inspection_protocol
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
+  yaml:
+    dependency: "direct main"
+    description:
+      name: yaml
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.2.1"
+sdks:
+  dart: ">=2.12.0 <3.0.0"
diff --git a/scheduler/pubspec.yaml b/scheduler/pubspec.yaml
new file mode 100644
index 0000000000..f567d479c8
--- /dev/null
+++ b/scheduler/pubspec.yaml
@@ -0,0 +1,15 @@
+name: cocoon_scheduler
+description: Flutter infrastructure scheduler
+version: 1.0.0
+publish_to: none
+
+environment:
+  sdk: '>=2.10.0 <3.0.0'
+
+dependencies:
+  protobuf: ^1.0.0
+  yaml: ^2.1.16
+
+dev_dependencies:
+  pedantic: ^1.10.0
+  test: ^1.16.0
diff --git a/scheduler/test/scheduler_test.dart b/scheduler/test/scheduler_test.dart
new file mode 100644
index 0000000000..0cba88ee5e
--- /dev/null
+++ b/scheduler/test/scheduler_test.dart
@@ -0,0 +1,183 @@
+// Copyright 2021 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:cocoon_scheduler/models/scheduler.pb.dart';
+import 'package:cocoon_scheduler/scheduler.dart';
+import 'package:test/test.dart';
+import 'package:yaml/yaml.dart';
+
+void main() {
+  group('scheduler config', () {
+    test('constructs graph with one target', () {
+      final YamlMap singleTargetConfig = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+    builder: builderA
+    properties:
+      test: abc
+      ''') as YamlMap;
+      final SchedulerConfig schedulerConfig = schedulerConfigFromYaml(singleTargetConfig);
+      expect(schedulerConfig.enabledBranches, <String>['master']);
+      expect(schedulerConfig.targets.length, 1);
+      final Target target = schedulerConfig.targets.first;
+      expect(target.bringup, false);
+      expect(target.name, 'A');
+      expect(target.properties, <String, String>{
+        'test': 'abc',
+      });
+      expect(target.builder, 'builderA');
+      expect(target.scheduler, SchedulerSystem.cocoon);
+      expect(target.testbed, 'linux-vm');
+      expect(target.timeout, 30);
+    });
+
+    test('throws exception when non-existent scheduler is given', () {
+      final YamlMap targetWithNonexistentScheduler = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+    scheduler: dashatar
+      ''') as YamlMap;
+      expect(() => schedulerConfigFromYaml(targetWithNonexistentScheduler), throwsA(isA<FormatException>()));
+    });
+
+    test('constructs graph with dependency chain', () {
+      final YamlMap dependentTargetConfig = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+  - name: B
+    dependencies:
+      - A
+  - name: C
+    dependencies:
+      - B
+      ''') as YamlMap;
+      final SchedulerConfig schedulerConfig = schedulerConfigFromYaml(dependentTargetConfig);
+      expect(schedulerConfig.targets.length, 3);
+      final Target a = schedulerConfig.targets.first;
+      final Target b = schedulerConfig.targets[1];
+      final Target c = schedulerConfig.targets[2];
+      expect(a.name, 'A');
+      expect(b.name, 'B');
+      expect(b.dependencies, <String>['A']);
+      expect(c.name, 'C');
+      expect(c.dependencies, <String>['B']);
+    });
+
+    test('constructs graph with parent with two dependents', () {
+      final YamlMap twoDependentTargetConfig = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+  - name: B1
+    dependencies:
+      - A
+  - name: B2
+    dependencies:
+      - A
+      ''') as YamlMap;
+      final SchedulerConfig schedulerConfig = schedulerConfigFromYaml(twoDependentTargetConfig);
+      expect(schedulerConfig.targets.length, 3);
+      final Target a = schedulerConfig.targets.first;
+      final Target b1 = schedulerConfig.targets[1];
+      final Target b2 = schedulerConfig.targets[2];
+      expect(a.name, 'A');
+      expect(b1.name, 'B1');
+      expect(b1.dependencies, <String>['A']);
+      expect(b2.name, 'B2');
+      expect(b2.dependencies, <String>['A']);
+    });
+
+    test('fails when there are cyclic targets', () {
+      final YamlMap configWithCycle = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+    dependencies:
+      - B
+  - name: B
+    dependencies:
+      - A
+      ''') as YamlMap;
+      expect(
+          () => schedulerConfigFromYaml(configWithCycle),
+          throwsA(
+            isA<FormatException>().having(
+              (FormatException e) => e.toString(),
+              'message',
+              contains('ERROR: A depends on B which does not exist'),
+            ),
+          ));
+    });
+
+    test('fails when there are duplicate targets', () {
+      final YamlMap configWithDuplicateTargets = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+  - name: A
+      ''') as YamlMap;
+      expect(
+          () => schedulerConfigFromYaml(configWithDuplicateTargets),
+          throwsA(
+            isA<FormatException>().having(
+              (FormatException e) => e.toString(),
+              'message',
+              contains('ERROR: A already exists in graph'),
+            ),
+          ));
+    });
+
+    test('fails when there are multiple dependencies', () {
+      final YamlMap configWithMultipleDependencies = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+  - name: B
+  - name: C
+    dependencies:
+      - A
+      - B
+      ''') as YamlMap;
+      expect(
+          () => schedulerConfigFromYaml(configWithMultipleDependencies),
+          throwsA(
+            isA<FormatException>().having(
+              (FormatException e) => e.toString(),
+              'message',
+              contains('ERROR: C has multiple dependencies which is not supported. Use only one dependency'),
+            ),
+          ));
+    });
+
+    test('fails when dependency does not exist', () {
+      final YamlMap configWithMissingTarget = loadYaml('''
+enabled_branches:
+  - master
+targets:
+  - name: A
+    dependencies:
+      - B
+      ''') as YamlMap;
+      expect(
+          () => schedulerConfigFromYaml(configWithMissingTarget),
+          throwsA(
+            isA<FormatException>().having(
+              (FormatException e) => e.toString(),
+              'message',
+              contains('ERROR: A depends on B which does not exist'),
+            ),
+          ));
+    });
+  });
+}
diff --git a/test_utilities/bin/config_test_runner.sh b/test_utilities/bin/config_test_runner.sh
index 6713344bc3..e24b6924b0 100755
--- a/test_utilities/bin/config_test_runner.sh
+++ b/test_utilities/bin/config_test_runner.sh
@@ -10,7 +10,7 @@ set -ex
 
 # Build and analyze
 echo "Running config tests on $1"
-pushd app_dart > /dev/null
+pushd scheduler > /dev/null
 flutter clean
 pub get
 
diff --git a/tests.yaml b/tests.yaml
index e50cfb2832..d21673865a 100644
--- a/tests.yaml
+++ b/tests.yaml
@@ -23,6 +23,9 @@ tasks:
   - task: app_dart
     script: test_utilities/bin/dart_test_runner.sh
 
+  - task: scheduler
+    script: test_utilities/bin/dart_test_runner.sh
+
   - task: app_flutter
     script: test_utilities/bin/flutter_test_runner.sh