Amazon API Gateway
Developer Guide

Amazon API Gateway Known Issues

Amazon API Gateway Known Issues for REST and WebSocket APIs

  • API Gateway does not support wildcard subdomain names (of the *.domain form). However, it does support wildcard certificates (certificates for wildcard subdomain names).

  • API Gateway does not support sharing a custom domain name across REST and WebSocket APIs.

  • The /ping and /sping paths are reserved for the service health check. Use of these for API root-level resources with custom domains will fail to produce the expected result.

  • API Gateway currently limits log events to 1024 bytes. Log events larger than 1024 bytes, such as request and response bodies, will be truncated by API Gateway before submission to CloudWatch Logs.

  • CloudWatch Metrics currently limits dimension names and values to 255 valid XML characters. (For more information, see the CloudWatch User Guide.) Dimension values are a function of user-defined names, including API name, label (stage) name, and resource name. When choosing these names, be careful not to exceed CloudWatch Metrics limits.

Amazon API Gateway Known Issues for WebSocket APIs

  • API Gateway supports message payloads up to 128 KB with a maximum frame size of 32 KB. If a message exceeds 32 KB, you must split it into multiple frames, each 32 KB or smaller. If a larger message is received, the connection is closed with code 1009.

Amazon API Gateway Known Issues for REST APIs

  • The plain text pipe character (|) is not supported for any request URL query string and must be URL-encoded.

  • The semicolon character (;) is not supported for any request URL query string and results in the data being split.

  • When using the API Gateway console to test an API, you may get an "unknown endpoint errors" response if a self-signed certificate is presented to the backend, the intermediate certificate is missing from the certificate chain, or any other unrecognizable certificate-related exceptions thrown by the backend.

  • For an API Resource or Method entity with a private integration, you should delete it after removing any hard-coded reference of a VpcLink. Otherwise, you have a dangling integration and receive an error stating that the VPC link is still in use even when the Resource or Method entity is deleted. This behavior does not apply when the private integration references VpcLink through a stage variable.

  • The following backends may not support SSL client authentication in a way that's compatible with API Gateway:

  • API Gateway supports most of the OpenAPI 2.0 specification and the OpenAPI 3.0 specification, with the following exceptions:

    • API Gateway models are defined using JSON schema draft 4, instead of the JSON schema used by OpenAPI.

    • The additionalProperties field is not supported in Models.

    • The discriminator parameter is not supported in any schema object.

    • The example tag is not supported.

    • exclusiveMinimum is not supported by API Gateway

    • The maxItems and minItems tags are not included in simple request validation. To work around this, update the model after import before doing validation.

    • oneOf is not supported by API Gateway

    • pattern is not supported by API Gateway

    • The readOnly field is not supported.

    • Response definitions of the "500": {"$ref": "#/responses/UnexpectedError"} form is not supported in the OpenAPI document root. To work around this, replace the reference by the inline schema.

    • Numbers of the Int32 or Int64 type is not supported. An example is shown as follows:

      "elementId": { "description": "Working Element Id", "format": "int32", "type": "number" }
    • Decimal number format type ("format": "decimal") is not supported in a schema definition.

    • In method responses, schema definition must be of an object type and cannot be of primitive types. For example, "schema": { "type": "string"} is not supported. However, you can work around this using the following object type:

      "schema": { "$ref": "#/definitions/StringResponse" } "definitions": { "StringResponse": { "type": "string" } }
  • API Gateway enacts the following restrictions and limitations when handling methods with either Lambda integration or HTTP integration.

    • Header names and query parameters are processed in a case-sensitive way.

    • The following headers may be dropped, remapped, or otherwise modified when sent to your integration endpoint or sent back by your integration endpoint:

      Header Name Request (http/http_proxy/lambda) Response (http/http_proxy/lambda)
      Age Passthrough Passthrough
      Accept Passthrough Dropped/Passthrough/Passthrough
      Accept-Charset Passthrough Passthrough
      Accept-Encoding Passthrough Passthrough
      Authorization Dropped (400) Remapped
      Connection Passthrough/Passthrough/Dropped Remapped
      Content-Encoding Passthrough/Dropped/Passthrough Passthrough
      Content-Length Passthrough (generated based on body) Passthrough
      Content-MD5 Dropped Remapped
      Content-Type Passthrough Passthrough
      Date Passthrough Remapped Overwritten
      Expect Dropped Dropped
      Host 5XX/5XX/Overwritten by Lambda Dropped
      Max-Forwards Dropped Remapped
      Pragma Passthrough Passthrough
      Proxy-Authenticate Dropped Dropped
      Range Passthrough Passthrough
      Referer Passthrough Passthrough
      Server Dropped Remapped Overwritten
      TE Dropped Dropped
      Transfer-Encoding Dropped/Dropped/Exception Dropped
      Trailer Dropped Dropped
      Upgrade Dropped Dropped
      User-Agent Passthrough Remapped
      Via Dropped/Dropped/Passthrough Passthrough/Dropped/Dropped
      Warn Passthrough Passthrough
      WWW-Authenticate Dropped Remapped
  • The Android SDK of an API generated by API Gateway uses the java.net.HttpURLConnection class. This class will throw an unhandled exception, on devices running Android 4.4 and earlier, for a 401 response resulted from remapping of the WWW-Authenticate header to X-Amzn-Remapped-WWW-Authenticate.

  • Unlike API Gateway-generated Java, Android and iOS SDKs of an API, the JavaScript SDK of an API generated by API Gateway does not support retries for 500-level errors.

  • The test invocation of a method uses the default content type of application/json and ignores specifications of any other content types.