Working with AWS Lambda proxy integrations for HTTP APIs

A Lambda proxy integration enables you to integrate an API route with a Lambda function. When a client calls your API, API Gateway sends the request to the Lambda function and returns the function's response to the client. For examples of creating an HTTP API, see Creating an HTTP API.

Payload format version

The payload format version specifies the format of the data that API Gateway sends to a Lambda integration, and how API Gateway interprets the response from Lambda. If you don't specify a payload format version, the AWS Management Console uses the latest version by default. If you create a Lambda integration by using the AWS CLI, AWS CloudFormation, or an SDK, you must specify a payloadFormatVersion. The supported values are 1.0 and 2.0.

The following examples show the structure of each payload format version.

Note

Format 2.0 doesn't have multiValueHeaders or multiValueQueryStringParameters fields. Duplicate headers are combined with commas and included in the headers field. Duplicate query strings are combined with commas and included in the queryStringParameters field.

Format 2.0 includes a new cookies field. All cookie headers in the request are combined with commas and added to the cookies field. In the response to the client, each cookie becomes a set-cookie header.

2.0

{
  "version": "2.0",
  "routeKey": "$default",
  "rawPath": "/my/path",
  "rawQueryString": "parameter1=value1&parameter1=value2&parameter2=value",
  "cookies": [
    "cookie1",
    "cookie2"
  ],
  "headers": {
    "Header1": "value1",
    "Header2": "value1,value2"
  },
  "queryStringParameters": {
    "parameter1": "value1,value2",
    "parameter2": "value"
  },
  "requestContext": {
    "accountId": "123456789012",
    "apiId": "api-id",
    "authentication": {
      "clientCert": {
        "clientCertPem": "CERT_CONTENT",
        "subjectDN": "www.example.com",
        "issuerDN": "Example issuer",
        "serialNumber": "a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1",
        "validity": {
          "notBefore": "May 28 12:30:02 2019 GMT",
          "notAfter": "Aug  5 09:36:04 2021 GMT"
        }
      }
    },
    "authorizer": {
      "jwt": {
        "claims": {
          "claim1": "value1",
          "claim2": "value2"
        },
        "scopes": [
          "scope1",
          "scope2"
        ]
      }
    },
    "domainName": "id.execute-api.us-east-1.amazonaws.com",
    "domainPrefix": "id",
    "http": {
      "method": "POST",
      "path": "/my/path",
      "protocol": "HTTP/1.1",
      "sourceIp": "IP",
      "userAgent": "agent"
    },
    "requestId": "id",
    "routeKey": "$default",
    "stage": "$default",
    "time": "12/Mar/2020:19:03:58 +0000",
    "timeEpoch": 1583348638390
  },
  "body": "Hello from Lambda",
  "pathParameters": {
    "parameter1": "value1"
  },
  "isBase64Encoded": false,
  "stageVariables": {
    "stageVariable1": "value1",
    "stageVariable2": "value2"
  }
}

1.0

{
  "version": "1.0",
  "resource": "/my/path",
  "path": "/my/path",
  "httpMethod": "GET",
  "headers": {
    "Header1": "value1",
    "Header2": "value2"
  },
  "multiValueHeaders": {
    "Header1": [
      "value1"
    ],
    "Header2": [
      "value1",
      "value2"
    ]
  },
  "queryStringParameters": {
    "parameter1": "value1",
    "parameter2": "value"
  },
  "multiValueQueryStringParameters": {
    "parameter1": [
      "value1",
      "value2"
    ],
    "parameter2": [
      "value"
    ]
  },
  "requestContext": {
    "accountId": "123456789012",
    "apiId": "id",
    "authorizer": {
      "claims": null,
      "scopes": null
    },
    "domainName": "id.execute-api.us-east-1.amazonaws.com",
    "domainPrefix": "id",
    "extendedRequestId": "request-id",
    "httpMethod": "GET",
    "identity": {
      "accessKey": null,
      "accountId": null,
      "caller": null,
      "cognitoAuthenticationProvider": null,
      "cognitoAuthenticationType": null,
      "cognitoIdentityId": null,
      "cognitoIdentityPoolId": null,
      "principalOrgId": null,
      "sourceIp": "IP",
      "user": null,
      "userAgent": "user-agent",
      "userArn": null,
      "clientCert": {
        "clientCertPem": "CERT_CONTENT",
        "subjectDN": "www.example.com",
        "issuerDN": "Example issuer",
        "serialNumber": "a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1:a1",
        "validity": {
          "notBefore": "May 28 12:30:02 2019 GMT",
          "notAfter": "Aug  5 09:36:04 2021 GMT"
        }
      }
    },
    "path": "/my/path",
    "protocol": "HTTP/1.1",
    "requestId": "id=",
    "requestTime": "04/Mar/2020:19:15:17 +0000",
    "requestTimeEpoch": 1583349317135,
    "resourceId": null,
    "resourcePath": "/my/path",
    "stage": "$default"
  },
  "pathParameters": null,
  "stageVariables": null,
  "body": "Hello from Lambda!",
  "isBase64Encoded": false
}

Lambda function response format

The payload format version determines the structure of the response that your Lambda function must return.

Lambda function response for format 1.0

With the 1.0 format version, Lambda integrations must return a response in the following format.

{
    "isBase64Encoded": true|false,
    "statusCode": httpStatusCode,
    "headers": { "headerName": "headerValue", ... },
    "multiValueHeaders": { "headerName": ["headerValue", "headerValue2", ...], ... },
    "body": "..."
}

Lambda function response for format 2.0

With the 2.0 format version, API Gateway can infer the response format for you. API Gateway makes the following assumptions if your Lambda function returns valid JSON and doesn't return a statusCode:

• isBase64Encoded is false.

• statusCode is 200.

• content-type is application/json.

• body is the function's response.

The following examples show the output of a Lambda function and API Gateway's interpretation.

Lambda function output	API Gateway interpretation
"Hello from Lambda!"	{ "isBase64Encoded": false, "statusCode": 200, "body": "Hello from Lambda!", "headers": { "Content-Type": "application/json" } }
{ "message": "Hello from Lambda!" }	{ "isBase64Encoded": false, "statusCode": 200, "body": "{ \"message\": \"Hello from Lambda!\" }", "headers": { "Content-Type": "application/json" } }

To customize the response, your Lambda function should return a response with the following format.

{
    "cookies" : ["cookie1", "cookie2"],
    "isBase64Encoded": true|false,
    "statusCode": httpStatusCode,
    "headers": { "headerName": "headerValue", ... },
    "body": "Hello from Lambda!"
}