Amazon Machine Learning
API Reference (API Version 2014-12-12)


Generates a prediction for the observation using the specified ML Model.

Note: Not all response parameters will be populated. Whether a response parameter is populated depends on the type of model requested.

Request Syntax

   "MLModelId": "string",
   "PredictEndpoint": "string",
   "Record": { 
      "string" : "string" 

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.

The request accepts the following data in JSON format.


A unique identifier of the MLModel.

Type: String

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

Pattern: [a-zA-Z0-9_.-]+

Required: Yes


Type: String

Required: Yes


A map of variable name-value pairs that represent an observation.

Type: String to string map

Required: Yes

Response Syntax

   "Prediction": { 
      "details": { 
         "string" : "string" 
      "predictedLabel": "string",
      "predictedScores": { 
         "string" : number 
      "predictedValue": number

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

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


The output from a Predict operation:

  • Details - Contains the following attributes: DetailsAttributes.PREDICTIVE_MODEL_TYPE - REGRESSION | BINARY | MULTICLASS DetailsAttributes.ALGORITHM - SGD

  • PredictedLabel - Present for either a BINARY or MULTICLASS MLModel request.

  • PredictedScores - Contains the raw classification score corresponding to each label.

  • PredictedValue - Present for a REGRESSION MLModel request.

Type: Prediction object


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


An error on the server occurred when trying to process a request.

HTTP Status Code: 500


An error on the client occurred. Typically, the cause is an invalid input value.

HTTP Status Code: 400


The subscriber exceeded the maximum number of operations. This exception can occur when listing objects such as DataSource.

HTTP Status Code: 400


The exception is thrown when a predict request is made to an unmounted MLModel.

HTTP Status Code: 400


A specified resource cannot be located.

HTTP Status Code: 400


The following is a sample request and response of the Predict operation.

Sample Request

Host: <hostname from the GetMLModel response EndpointUrl object>
x-amz-Date: <Date>
Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=contenttype;date;host;user-agent;x-amz-date;x-amz-target;x-amzn-requestid,Signature=<Signature>
User-Agent: <UserAgentString>
Content-Type: application/x-amz-json-1.1
Content-Length: <PayloadSizeBytes>
Connection: Keep-Alive
X-Amz-Target: AmazonML_20141212.Predict
{"MLModelId" : "exampleMLModelId",
 "Record" : {
   "ExampleData" : "exampleValue"
 "PredictEndpoint" : "<realtime endpoint from Amazon Machine Learning for exampleMLModelId>"

Sample Response

HTTP/1.1 200 OK
x-amzn-RequestId: <RequestId>
Content-Type: application/x-amz-json-1.1
Content-Length: <PayloadSizeBytes>
Date: <Date>
{"PredictedLabel" : "0"
 "PredictedScores" : {
   "0" : "0.446588516"
 "Details" : {
   "PredictiveModelType" : "BINARY",
   "Algorithm" : "SGD"

See Also

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