Calling SageMaker from API Gateway Without Lambda

This note describes how to set up the integration using API Gateway's integration request feature, eliminating the need for AWS Lambda functions.

Takahiro Iwasa

2023-07-13

2 min read

This note describes how to set up the integration using API Gateway’s integration request feature, eliminating the need for AWS Lambda functions.

Finding SageMaker Inference Endpoint

Navigate to SageMaker Console and go to Endpoint summary > URL.

The endpoint format is as follows:

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https://runtime.sagemaker.<ENDPOINT_REGION>.amazonaws.com/endpoints/<ENDPOINT_NAME>/invocations

Building REST API Integrated with SageMaker Inference Endpoint

Select REST API in the API Gateway Console.

Assign a name to your API.

Select Actions -> Create Method.

Choose the HTTP method type (POST is used in this example).

Configure integration request:

• Integration type: AWS Service
• AWS Service: SageMaker Runtime (NOT SageMaker)
• HTTP method: POST
• Action Type: Use path override
• Path override: endpoints/<ENDPOINT_NAME>/invocations
• Execution role: IAM role for API (must include the sagemaker:InvokeEndpoint action)
• Content Handling: Passthrough

If your model accepts binary input (e.g., images), add the relevant MIME type (e.g., image/*) in the Binary Media Types.

Without this configuration, you may encounter the following error:

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{
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  "ErrorCode": "CLIENT_ERROR_FROM_MODEL",
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  "LogStreamArn": "arn:aws:logs:ap-northeast-1:xxxxxxxxxxxx:log-group:/aws/sagemaker/Endpoints/<ENDPOINT_NAME>",
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  "Message": "Received client error (400) from primary with message \"unable to evaluate payload provided\". See https://ap-northeast-1.console.aws.amazon.com/cloudwatch/home?region=ap-northeast-1#logEventViewer:group=/aws/sagemaker/Endpoints/<ENDPOINT_NAME> in account xxxxxxxxxxxx for more information.",
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  "OriginalMessage": "unable to evaluate payload provided",
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  "OriginalStatusCode": 400
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}

Select Deploy API in the API Gateway console.

Assign a stage for the deployment.

Once deployed, the API endpoint will be available for testing.

Testing

You can test the deployed API using the following curl command:

curl --location '<API_ENDPOINT>' \
  --header 'Content-Type: image/jpeg' \
  --header 'Accept: application/json' \
  --data-binary '@/path/to/image.jpg'

About the author

Takahiro Iwasa

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Software Developer

This blog shares technical notes from hands-on projects—architecture, implementation, and AWS service integrations.