diff --git a/.github/workflows/rubocop.yml b/.github/workflows/rubocop.yml
index daadb4c6..982bfd3b 100644
--- a/.github/workflows/rubocop.yml
+++ b/.github/workflows/rubocop.yml
@@ -26,5 +26,5 @@ jobs:
       with:
         ruby-version: 3.0
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
-    - name: Run rubocop
+    - name: Generate docs
       run: bundle exec rubocop --config .rubocop.yml
diff --git a/lib/nylas.rb b/lib/nylas.rb
index 74493af3..8010ba5e 100644
--- a/lib/nylas.rb
+++ b/lib/nylas.rb
@@ -32,8 +32,13 @@
 require_relative "nylas/resources/calendars"
 require_relative "nylas/resources/connectors"
 require_relative "nylas/resources/credentials"
+require_relative "nylas/resources/drafts"
 require_relative "nylas/resources/events"
 require_relative "nylas/resources/grants"
 require_relative "nylas/resources/messages"
+require_relative "nylas/resources/smart_compose"
+require_relative "nylas/resources/threads"
 require_relative "nylas/resources/redirect_uris"
 require_relative "nylas/resources/webhooks"
+
+require_relative "nylas/utils/file_utils"
diff --git a/lib/nylas/client.rb b/lib/nylas/client.rb
index 00303569..45045e12 100644
--- a/lib/nylas/client.rb
+++ b/lib/nylas/client.rb
@@ -33,6 +33,13 @@ def applications
       Applications.new(self)
     end
 
+    # The auth resources for your Nylas application.
+    #
+    # @return [Nylas::Auth] Auth resources for your Nylas application.
+    def auth
+      Auth.new(self)
+    end
+
     # The calendar resources for your Nylas application.
     #
     # @return [Nylas::Calendars] Calendar resources for your Nylas application.
@@ -47,6 +54,13 @@ def connectors
       Connectors.new(self)
     end
 
+    # The draft resources for your Nylas application.
+    #
+    # @return [Nylas::Drafts] Draft resources for your Nylas application.
+    def drafts
+      Drafts.new(self)
+    end
+
     # The event resources for your Nylas application.
     #
     # @return [Nylas::Events] Event resources for your Nylas application
@@ -61,11 +75,11 @@ def messages
       Messages.new(self)
     end
 
-    # The auth resources for your Nylas application.
+    # The thread resources for your Nylas application.
     #
-    # @return [Nylas::Auth] Auth resources for your Nylas application.
-    def auth
-      Auth.new(self)
+    # @return [Nylas::Threads] Thread resources for your Nylas application.
+    def threads
+      Threads.new(self)
     end
 
     # The webhook resources for your Nylas application.
diff --git a/lib/nylas/handler/api_operations.rb b/lib/nylas/handler/api_operations.rb
index 209cc6b6..e3ed406f 100644
--- a/lib/nylas/handler/api_operations.rb
+++ b/lib/nylas/handler/api_operations.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require_relative "http_client"
+
 module Nylas
   # Allows resources to perform API operations on the Nylas API endpoints without exposing the HTTP
   # client to the end user.
diff --git a/lib/nylas/handler/http_client.rb b/lib/nylas/handler/http_client.rb
index d2f9eea4..cfc95cf7 100644
--- a/lib/nylas/handler/http_client.rb
+++ b/lib/nylas/handler/http_client.rb
@@ -77,17 +77,21 @@ def build_request(
       url = path
       url = add_query_params_to_url(url, query)
       resulting_headers = default_headers.merge(headers).merge(auth_header(api_key))
-      serialized_payload = payload&.to_json
+      if !payload.nil? && !payload["multipart"]
+        payload = payload&.to_json
+        resulting_headers["Content-type"] = "application/json"
+      elsif !payload.nil? && payload["multipart"]
+        payload.delete("multipart")
+      end
 
-      { method: method, url: url, payload: serialized_payload, headers: resulting_headers, timeout: timeout }
+      { method: method, url: url, payload: payload, headers: resulting_headers, timeout: timeout }
     end
 
     # Sets the default headers for API requests.
     def default_headers
       @default_headers ||= {
         "X-Nylas-API-Wrapper" => "ruby",
-        "User-Agent" => "Nylas Ruby SDK #{Nylas::VERSION} - #{RUBY_VERSION}",
-        "Content-type" => "application/json"
+        "User-Agent" => "Nylas Ruby SDK #{Nylas::VERSION} - #{RUBY_VERSION}"
       }
     end
 
@@ -141,11 +145,11 @@ def error_hash_to_exception(response, status_code, path)
         NylasOAuthError.new(response[:error], response[:error_description], response[:error_uri],
                             response[:error_code], status_code)
       else
-        throw_error(response)
+        throw_error(response, status_code)
       end
     end
 
-    def throw_error(response)
+    def throw_error(response, status_code)
       error_obj = response[:error]
       provider_error = error_obj.fetch(:provider_error, nil)
 
@@ -157,7 +161,7 @@ def throw_error(response)
     #
     # @return [String] Processed URL, including query params.
     def add_query_params_to_url(url, query)
-      unless query.empty?
+      unless query.nil? || query.empty?
         uri = URI.parse(url)
         query = custom_params(query)
         params = URI.decode_www_form(uri.query || "") + query.to_a
diff --git a/lib/nylas/resources/drafts.rb b/lib/nylas/resources/drafts.rb
new file mode 100644
index 00000000..654dad60
--- /dev/null
+++ b/lib/nylas/resources/drafts.rb
@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+require_relative "resource"
+require_relative "../handler/api_operations"
+require_relative "../utils/file_utils"
+
+module Nylas
+  # Nylas Drafts API
+  class Drafts < Resource
+    include ApiOperations::Get
+    include ApiOperations::Post
+    include ApiOperations::Put
+    include ApiOperations::Delete
+
+    # Return all drafts.
+    #
+    # @param identifier [String] Grant ID or email account to query.
+    # @param query_params [Hash, nil] Query params to pass to the request.
+    # @return [Array(Array(Hash), String)] The list of drafts and API Request ID.
+    def list(identifier:, query_params: nil)
+      get(
+        path: "#{api_uri}/v3/grants/#{identifier}/drafts",
+        query_params: query_params
+      )
+    end
+
+    # Return an draft.
+    #
+    # @param identifier [String] Grant ID or email account to query.
+    # @param draft_id [String] The id of the draft to return.
+    # @return [Array(Hash, String)] The draft and API request ID.
+    def find(identifier:, draft_id:)
+      get(
+        path: "#{api_uri}/v3/grants/#{identifier}/drafts/#{draft_id}"
+      )
+    end
+
+    # Create an draft.
+    #
+    # @param identifier [String] Grant ID or email account in which to create the draft.
+    # @param request_body [Hash] The values to create the message with.
+    #   If you're attaching files, you must pass an array of [File] objects, or
+    #   you can use {FileUtils::attach_file_request_builder} to build each object attach.
+    # @return [Array(Hash, String)] The created draft and API Request ID.
+    def create(identifier:, request_body:)
+      form_body, opened_files = FileUtils.build_form_request(request_body)
+      response = post(
+        path: "#{api_uri}/v3/grants/#{identifier}/drafts",
+        request_body: form_body
+      )
+
+      opened_files.each(&:close)
+
+      response
+    end
+
+    # Update an draft.
+    #
+    # @param identifier [String] Grant ID or email account in which to update the draft.
+    # @param draft_id [String] The id of the draft to update.
+    # @param request_body [Hash] The values to create the message with.
+    #   If you're attaching files, you must pass an array of [File] objects, or
+    #   you can use {FileUtils::attach_file_request_builder} to build each object attach.
+    # @return [Array(Hash, String)] The updated draft and API Request ID.
+    def update(identifier:, draft_id:, request_body:)
+      form_body, opened_files = FileUtils.build_form_request(request_body)
+
+      response = put(
+        path: "#{api_uri}/v3/grants/#{identifier}/drafts/#{draft_id}",
+        request_body: form_body
+      )
+
+      opened_files.each(&:close)
+
+      response
+    end
+
+    # Delete an draft.
+    #
+    # @param identifier [String] Grant ID or email account from which to delete an object.
+    # @param draft_id [String] The id of the draft to delete.
+    # @return [Array(TrueClass, String)] True and the API Request ID for the delete operation.
+    def destroy(identifier:, draft_id:)
+      _, request_id = delete(
+        path: "#{api_uri}/v3/grants/#{identifier}/drafts/#{draft_id}"
+      )
+
+      [true, request_id]
+    end
+  end
+end
diff --git a/lib/nylas/resources/messages.rb b/lib/nylas/resources/messages.rb
index c3d7fed7..976895b0 100644
--- a/lib/nylas/resources/messages.rb
+++ b/lib/nylas/resources/messages.rb
@@ -1,15 +1,27 @@
 # frozen_string_literal: true
 
 require_relative "resource"
+require_relative "smart_compose"
 require_relative "../handler/api_operations"
+require_relative "../utils/file_utils"
 
 module Nylas
   # Nylas Messages API
   class Messages < Resource
     include ApiOperations::Get
+    include ApiOperations::Post
     include ApiOperations::Put
     include ApiOperations::Delete
 
+    attr_reader :smart_compose
+
+    # Initializes the messages resource.
+    # @param sdk_instance [Nylas::API] The API instance to which the resource is bound.
+    def initialize(sdk_instance)
+      super(sdk_instance)
+      @smart_compose = SmartCompose.new(sdk_instance)
+    end
+
     # Return all messages.
     #
     # @param identifier [String] Grant ID or email account to query.
@@ -26,7 +38,6 @@ def list(identifier:, query_params: nil)
     #
     # @param identifier [String] Grant ID or email account to query.
     # @param message_id [String] The id of the message to return.
-    #   Use "primary" to refer to the primary message associated with grant.
     # @return [Array(Hash, String)] The message and API request ID.
     def find(identifier:, message_id:)
       get(
@@ -38,7 +49,6 @@ def find(identifier:, message_id:)
     #
     # @param identifier [String] Grant ID or email account in which to update an object.
     # @param message_id [String] The id of the message to update.
-    #   Use "primary" to refer to the primary message associated with grant.
     # @param request_body [Hash] The values to update the message with
     # @return [Array(Hash, String)] The updated message and API Request ID.
     def update(identifier:, message_id:, request_body:)
@@ -52,7 +62,6 @@ def update(identifier:, message_id:, request_body:)
     #
     # @param identifier [String] Grant ID or email account from which to delete an object.
     # @param message_id [String] The id of the message to delete.
-    #   Use "primary" to refer to the primary message associated with grant.
     # @return [Array(TrueClass, String)] True and the API Request ID for the delete operation.
     def destroy(identifier:, message_id:)
       _, request_id = delete(
@@ -61,5 +70,57 @@ def destroy(identifier:, message_id:)
 
       [true, request_id]
     end
+
+    # Send a message.
+    #
+    # @param identifier [String] Grant ID or email account from which to delete an object.
+    # @param request_body [Hash] The values to create the message with.
+    #   If you're attaching files, you must pass an array of [File] objects, or
+    #   you can use {FileUtils::attach_file_request_builder} to build each object attach.
+    # @return [Array(Hash, String)] The sent message and the API Request ID.
+    def send(identifier:, request_body:)
+      form_body, opened_files = FileUtils.build_form_request(request_body)
+
+      response = post(
+        path: "#{api_uri}/v3/grants/#{identifier}/messages/send",
+        request_body: form_body
+      )
+
+      opened_files.each(&:close)
+
+      response
+    end
+
+    # Retrieve your scheduled messages.
+    #
+    # @param identifier [String] Grant ID or email account from which to find the scheduled message from.
+    # @param schedule_id [String] The id of the scheduled message to stop.
+    # @return [Array(Hash, String)] The list of scheduled messages and the API Request ID.
+    def list_scheduled_messages(identifier:, schedule_id:)
+      get(
+        path: "#{api_uri}/v3/grants/#{identifier}/messages/schedules/#{schedule_id}"
+      )
+    end
+
+    # Retrieve your scheduled messages.
+    #
+    # @param identifier [String] Grant ID or email account from which to list the scheduled messages from.
+    # @return [Array(Hash, String)] The scheduled message and the API Request ID.
+    def find_scheduled_messages(identifier:)
+      get(
+        path: "#{api_uri}/v3/grants/#{identifier}/messages/schedules"
+      )
+    end
+
+    # Stop a scheduled message.
+    #
+    # @param identifier [String] Grant ID or email account from which to list the scheduled messages from.
+    # @param schedule_id [String] The id of the scheduled message to stop..
+    # @return [Array(Hash, String)] The scheduled message and the API Request ID.
+    def stop_scheduled_messages(identifier:, schedule_id:)
+      delete(
+        path: "#{api_uri}/v3/grants/#{identifier}/messages/schedules/#{schedule_id}"
+      )
+    end
   end
 end
diff --git a/lib/nylas/resources/smart_compose.rb b/lib/nylas/resources/smart_compose.rb
new file mode 100644
index 00000000..5c3e95c2
--- /dev/null
+++ b/lib/nylas/resources/smart_compose.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require_relative "resource"
+require_relative "../handler/api_operations"
+
+module Nylas
+  # Nylas Smart Compose API
+  class SmartCompose < Resource
+    include ApiOperations::Post
+
+    # Compose a message.
+    #
+    # @param identifier [String] Grant ID or email account to generate a message suggestion for.
+    # @param request_body [Hash] The prompt that smart compose will use to generate a message suggestion.
+    # @return [Array(Hash, String)] The generated message and API Request ID.
+    def compose_message(identifier:, request_body:)
+      post(
+        path: "#{api_uri}/v3/grants/#{identifier}/messages/smart-compose",
+        request_body: request_body
+      )
+    end
+
+    # Compose a message reply.
+    #
+    # @param identifier [String] Grant ID or email account to generate a message suggestion for.
+    # @param message_id [String] The id of the message to reply to.
+    # @param request_body [Hash] The prompt that smart compose will use to generate a message reply suggestion.
+    # @return [Array(Hash, String)] The generated message reply and API Request ID.
+    def compose_message_reply(identifier:, message_id:, request_body:)
+      post(
+        path: "#{api_uri}/v3/grants/#{identifier}/messages/#{message_id}/smart-compose",
+        request_body: request_body
+      )
+    end
+  end
+end
diff --git a/lib/nylas/resources/threads.rb b/lib/nylas/resources/threads.rb
new file mode 100644
index 00000000..cfcea5d1
--- /dev/null
+++ b/lib/nylas/resources/threads.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require_relative "resource"
+require_relative "../handler/api_operations"
+
+module Nylas
+  # Nylas Threads API
+  class Threads < Resource
+    include ApiOperations::Get
+    include ApiOperations::Put
+    include ApiOperations::Delete
+
+    # Return all threads.
+    #
+    # @param identifier [String] Grant ID or email account to query.
+    # @param query_params [Hash] Query params to pass to the request.
+    # @return [Array(Array(Hash), String)] The list of threads and API Request ID.
+    def list(identifier:, query_params: nil)
+      get(
+        path: "#{api_uri}/v3/grants/#{identifier}/threads",
+        query_params: query_params
+      )
+    end
+
+    # Return an thread.
+    #
+    # @param identifier [String] Grant ID or email account to query.
+    # @param thread_id [String] The id of the thread to return.
+    # @return [Array(Hash, String)] The thread and API request ID.
+    def find(identifier:, thread_id:)
+      get(
+        path: "#{api_uri}/v3/grants/#{identifier}/threads/#{thread_id}"
+      )
+    end
+
+    # Update an thread.
+    #
+    # @param identifier [String] Grant ID or email account in which to update the thread.
+    # @param thread_id [String] The id of the thread to update.
+    # @param request_body [Hash] The values to update the thread with
+    # @return [Array(Hash, String)] The updated thread and API Request ID.
+    def update(identifier:, thread_id:, request_body:)
+      put(
+        path: "#{api_uri}/v3/grants/#{identifier}/threads/#{thread_id}",
+        request_body: request_body
+      )
+    end
+
+    # Delete an thread.
+    #
+    # @param identifier [String] Grant ID or email account from which to delete the thread.
+    # @param thread_id [String] The id of the thread to delete.
+    # @return [Array(TrueClass, String)] True and the API Request ID for the delete operation.
+    def destroy(identifier:, thread_id:)
+      _, request_id = delete(
+        path: "#{api_uri}/v3/grants/#{identifier}/threads/#{thread_id}"
+      )
+
+      [true, request_id]
+    end
+  end
+end
diff --git a/lib/nylas/utils/file_utils.rb b/lib/nylas/utils/file_utils.rb
new file mode 100644
index 00000000..75b15d66
--- /dev/null
+++ b/lib/nylas/utils/file_utils.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "mime/types"
+
+module Nylas
+  # A collection of file-related utilities.
+  module FileUtils
+    # Build a form request for the API.
+    # @param request_body The values to create the message with.
+    # @return The form data to send to the API and the opened files.
+    # @!visibility private
+    def self.build_form_request(request_body)
+      attachments = request_body.delete(:attachments) || request_body.delete("attachments") || []
+      message_payload = request_body.to_json
+
+      # Prepare the data to return
+      form_data = {}
+      opened_files = []
+
+      attachments.each_with_index do |attachment, index|
+        file = attachment[:content] || attachment["content"]
+        form_data.merge!({ "file#{index}" => file })
+        opened_files << file
+      end
+
+      form_data.merge!({ "multipart" => true, "message" => message_payload })
+
+      [form_data, opened_files]
+    end
+
+    # Build the request to attach a file to a message/draft object.
+    # @param file_path [String] The path to the file to attach.
+    # @return [Hash] The request that will attach the file to the message/draft
+    def self.attach_file_request_builder(file_path)
+      filename = File.basename(file_path)
+      content_type = MIME::Types.type_for(file_path).first.to_s
+      content_type = "application/octet-stream" if content_type.empty?
+      size = File.size(file_path)
+      content = File.new(file_path, "rb")
+
+      {
+        filename: filename,
+        content_type: content_type,
+        size: size,
+        content: content
+      }
+    end
+  end
+end
diff --git a/nylas.gemspec b/nylas.gemspec
index 18e3bd99..897570a3 100644
--- a/nylas.gemspec
+++ b/nylas.gemspec
@@ -11,6 +11,7 @@ Gem::Specification.new do |gem|
   gem.license = "MIT"
 
   # Runtime dependencies
+  gem.add_runtime_dependency "mime-types", "~> 3.5", ">= 3.5.1"
   gem.add_runtime_dependency "rest-client", "~> 2.1", "< 3.0"
   gem.add_runtime_dependency "yajl-ruby", "~> 1.4.3", ">= 1.2.1"