Enable CORS on a resource using the API Gateway import API - Amazon API Gateway
Example Options methodExample API

Enable CORS on a resource using the API Gateway import API

If you are using the API Gateway Import API, you can set up CORS support using an OpenAPI file. You must first define an OPTIONS method in your resource that returns the required headers.

Note

Web browsers expect Access-Control-Allow-Headers, and Access-Control-Allow-Origin headers to be set up in each API method that accepts CORS requests. In addition, some browsers first make an HTTP request to an OPTIONS method in the same resource, and then expect to receive the same headers.

Example Options method

The following example creates an OPTIONS method for a mock integration.

OpenAPI 3.0
/users:
  options:
    summary: CORS support
    description: |
      Enable CORS by returning correct headers
    tags:
    - CORS
    responses:
      200:
        description: Default response for CORS method
        headers:
          Access-Control-Allow-Origin:
            schema:
              type: "string"
          Access-Control-Allow-Methods:
            schema:
              type: "string"
          Access-Control-Allow-Headers:
            schema:
              type: "string"
        content: {}
    x-amazon-apigateway-integration:
      type: mock
      requestTemplates:
        application/json: "{\"statusCode\": 200}"
      passthroughBehavior: "never"
      responses:
        default:
          statusCode: "200"
          responseParameters:
            method.response.header.Access-Control-Allow-Headers: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key'"
            method.response.header.Access-Control-Allow-Methods: "'*'"
            method.response.header.Access-Control-Allow-Origin: "'*'"
OpenAPI 2.0
/users: 
   options:
      summary: CORS support
      description: |
        Enable CORS by returning correct headers
      consumes:
        - "application/json"
      produces:
        - "application/json"
      tags:
        - CORS
      x-amazon-apigateway-integration:
        type: mock
        requestTemplates: "{\"statusCode\": 200}"
        passthroughBehavior: "never"
        responses:
          "default":
            statusCode: "200"
            responseParameters:
              method.response.header.Access-Control-Allow-Headers : "'Content-Type,X-Amz-Date,Authorization,X-Api-Key'"
              method.response.header.Access-Control-Allow-Methods : "'*'"
              method.response.header.Access-Control-Allow-Origin : "'*'"
      responses:
        200:
          description: Default response for CORS method
          headers:
            Access-Control-Allow-Headers:
              type: "string"
            Access-Control-Allow-Methods:
              type: "string"
            Access-Control-Allow-Origin:
              type: "string"

Once you have configured the OPTIONS method for your resource, you can add the required headers to the other methods in the same resource that need to accept CORS requests.

  1. Declare the Access-Control-Allow-Origin and Headers to the response types.

    OpenAPI 3.0
        responses:
      200:
        description: Default response for CORS method
        headers:
          Access-Control-Allow-Origin:
            schema:
              type: "string"
          Access-Control-Allow-Methods:
            schema:
              type: "string"
          Access-Control-Allow-Headers:
            schema:
              type: "string"
        content: {}
    OpenAPI 2.0
        responses:
        200:
          description: Default response for CORS method
          headers:
            Access-Control-Allow-Headers:
              type: "string"
            Access-Control-Allow-Methods:
              type: "string"
            Access-Control-Allow-Origin:
              type: "string"

  2. In the x-amazon-apigateway-integration tag, set up the mapping for those headers to your static values:

    OpenAPI 3.0
        responses:
        default:
          statusCode: "200"
          responseParameters:
            method.response.header.Access-Control-Allow-Headers: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key'"
            method.response.header.Access-Control-Allow-Methods: "'*'"
            method.response.header.Access-Control-Allow-Origin: "'*'"
          responseTemplates:
            application/json: |
              {}
    OpenAPI 2.0
        responses:
          "default":
            statusCode: "200"
            responseParameters:
              method.response.header.Access-Control-Allow-Headers : "'Content-Type,X-Amz-Date,Authorization,X-Api-Key'"
              method.response.header.Access-Control-Allow-Methods : "'*'"
              method.response.header.Access-Control-Allow-Origin : "'*'"

Example API

The following example creates a complete API with an OPTIONS method and a GET method with an HTTP integration.

OpenAPI 3.0
openapi: "3.0.1"
info:
  title: "cors-api"
  description: "cors-api"
  version: "2024-01-16T18:36:01Z"
servers:
- url: "/{basePath}"
  variables:
    basePath:
      default: "/test"
paths:
  /:
    get:
      operationId: "GetPet"
      responses:
        "200":
          description: "200 response"
          headers:
            Access-Control-Allow-Origin:
              schema:
                type: "string"
          content: {}
      x-amazon-apigateway-integration:
        httpMethod: "GET"
        uri: "http://petstore.execute-api.us-east-1.amazonaws.com/petstore/pets"
        responses:
          default:
            statusCode: "200"
            responseParameters:
              method.response.header.Access-Control-Allow-Origin: "'*'"
        passthroughBehavior: "never"
        type: "http"
    options:
      responses:
        "200":
          description: "200 response"
          headers:
            Access-Control-Allow-Origin:
              schema:
                type: "string"
            Access-Control-Allow-Methods:
              schema:
                type: "string"
            Access-Control-Allow-Headers:
              schema:
                type: "string"
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Empty"
      x-amazon-apigateway-integration:
        responses:
          default:
            statusCode: "200"
            responseParameters:
              method.response.header.Access-Control-Allow-Methods: "'GET,OPTIONS'"
              method.response.header.Access-Control-Allow-Headers: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key'"
              method.response.header.Access-Control-Allow-Origin: "'*'"
        requestTemplates:
          application/json: "{\"statusCode\": 200}"
        passthroughBehavior: "never"
        type: "mock"
components:
  schemas:
    Empty:
      type: "object"
OpenAPI 2.0 
swagger: "2.0"
info:
  description: "cors-api"
  version: "2024-01-16T18:36:01Z"
  title: "cors-api"
basePath: "/test"
schemes:
- "https"
paths:
  /:
    get:
      operationId: "GetPet"
      produces:
      - "application/json"
      responses:
        "200":
          description: "200 response"
          headers:
            Access-Control-Allow-Origin:
              type: "string"
      x-amazon-apigateway-integration:
        httpMethod: "GET"
        uri: "http://petstore.execute-api.us-east-1.amazonaws.com/petstore/pets"
        responses:
          default:
            statusCode: "200"
            responseParameters:
              method.response.header.Access-Control-Allow-Origin: "'*'"
        passthroughBehavior: "never"
        type: "http"
    options:
      consumes:
      - "application/json"
      produces:
      - "application/json"
      responses:
        "200":
          description: "200 response"
          schema:
            $ref: "#/definitions/Empty"
          headers:
            Access-Control-Allow-Origin:
              type: "string"
            Access-Control-Allow-Methods:
              type: "string"
            Access-Control-Allow-Headers:
              type: "string"
      x-amazon-apigateway-integration:
        responses:
          default:
            statusCode: "200"
            responseParameters:
              method.response.header.Access-Control-Allow-Methods: "'GET,OPTIONS'"
              method.response.header.Access-Control-Allow-Headers: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key'"
              method.response.header.Access-Control-Allow-Origin: "'*'"
        requestTemplates:
          application/json: "{\"statusCode\": 200}"
        passthroughBehavior: "never"
        type: "mock"
definitions:
  Empty:
    type: "object"