InvokeEndpointAsync - Amazon SageMaker
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After you deploy a model into production using Amazon SageMaker hosting services, your client applications use this API to get inferences from the model hosted at the specified endpoint in an asynchronous manner.

Inference requests sent to this API are enqueued for asynchronous processing. The processing of the inference request may or may not complete before the you receive a response from this API. The response from this API will not contain the result of the inference request but contain information about where you can locate it.

Amazon SageMaker strips all POST headers except those supported by the API. Amazon SageMaker might add additional headers. You should not rely on the behavior of headers outside those enumerated in the request syntax.

Calls to InvokeEndpointAsync are authenticated by using Amazon Signature Version 4. For information, see Authenticating Requests (Amazon Signature Version 4) in the Amazon S3 API Reference.

Request Syntax

POST /endpoints/EndpointName/async-invocations HTTP/1.1 X-Amzn-SageMaker-Content-Type: ContentType X-Amzn-SageMaker-Accept: Accept X-Amzn-SageMaker-Custom-Attributes: CustomAttributes X-Amzn-SageMaker-Inference-Id: InferenceId X-Amzn-SageMaker-InputLocation: InputLocation X-Amzn-SageMaker-RequestTTLSeconds: RequestTTLSeconds

URI Request Parameters

The request uses the following URI parameters.


The desired MIME type of the inference in the response.

Length Constraints: Maximum length of 1024.

Pattern: \p{ASCII}*


The MIME type of the input data in the request body.

Length Constraints: Maximum length of 1024.

Pattern: \p{ASCII}*


Provides additional information about a request for an inference submitted to a model hosted at an Amazon SageMaker endpoint. The information is an opaque value that is forwarded verbatim. You could use this value, for example, to provide an ID that you can use to track a request or to provide other metadata that a service endpoint was programmed to process. The value must consist of no more than 1024 visible US-ASCII characters as specified in Section 3.3.6. Field Value Components of the Hypertext Transfer Protocol (HTTP/1.1).

The code in your model is responsible for setting or updating any custom attributes in the response. If your code does not set this value in the response, an empty value is returned. For example, if a custom attribute represents the trace ID, your model can prepend the custom attribute with Trace ID: in your post-processing function.

This feature is currently supported in the Amazon SDKs but not in the Amazon SageMaker Python SDK.

Length Constraints: Maximum length of 1024.

Pattern: \p{ASCII}*


The name of the endpoint that you specified when you created the endpoint using the CreateEndpoint API.

Length Constraints: Maximum length of 63.

Pattern: ^[a-zA-Z0-9](-*[a-zA-Z0-9])*

Required: Yes


The identifier for the inference request. Amazon SageMaker will generate an identifier for you if none is specified.

Length Constraints: Minimum length of 1. Maximum length of 64.

Pattern: \A\S[\p{Print}]*\z


The Amazon S3 URI where the inference request payload is stored.

Length Constraints: Minimum length of 1. Maximum length of 1024.

Pattern: ^(https|s3)://([^/]+)/?(.*)$

Required: Yes


Maximum age in seconds a request can be in the queue before it is marked as expired.

Valid Range: Minimum value of 60. Maximum value of 21600.

Request Body

The request does not have a request body.

Response Syntax

HTTP/1.1 202 X-Amzn-SageMaker-OutputLocation: OutputLocation Content-type: application/json { "InferenceId": "string" }

Response Elements

If the action is successful, the service sends back an HTTP 202 response.

The response returns the following HTTP headers.


The Amazon S3 URI where the inference response payload is stored.

Length Constraints: Maximum length of 1024.

Pattern: \p{ASCII}*

The following data is returned in JSON format by the service.


Identifier for an inference request. This will be the same as the InferenceId specified in the input. Amazon SageMaker will generate an identifier for you if you do not specify one.

Type: String

Length Constraints: Maximum length of 1024.

Pattern: \p{ASCII}*


For information about the errors that are common to all actions, see Common Errors.


An internal failure occurred.

HTTP Status Code: 500


The service is unavailable. Try your call again.

HTTP Status Code: 503


Inspect your request and try again.

HTTP Status Code: 400

See Also

For more information about using this API in one of the language-specific Amazon SDKs, see the following: