StartModel - Amazon Lookout for Vision API Reference


Starts the running of the version of an Amazon Lookout for Vision model. Starting a model takes a while to complete. To check the current state of the model, use DescribeModel.

A model is ready to use when its status is HOSTED.

Once the model is running, you can detect custom labels in new images by calling DetectAnomalies.


You are charged for the amount of time that the model is running. To stop a running model, call StopModel.

This operation requires permissions to perform the lookoutvision:StartModel operation.

Request Syntax

POST /2020-11-20/projects/projectName/models/modelVersion/start HTTP/1.1 X-Amzn-Client-Token: ClientToken Content-type: application/json { "MaxInferenceUnits": number, "MinInferenceUnits": number }

URI Request Parameters

The request uses the following URI parameters.


ClientToken is an idempotency token that ensures a call to StartModel completes only once. You choose the value to pass. For example, An issue might prevent you from getting a response from StartModel. In this case, safely retry your call to StartModel by using the same ClientToken parameter value.

If you don't supply a value for ClientToken, the AWS SDK you are using inserts a value for you. This prevents retries after a network error from making multiple start requests. You'll need to provide your own value for other use cases.

An error occurs if the other input parameters are not the same as in the first request. Using a different value for ClientToken is considered a new call to StartModel. An idempotency token is active for 8 hours.

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

Pattern: ^[a-zA-Z0-9-]+$


The version of the model that you want to start.

Length Constraints: Minimum length of 1. Maximum length of 10.

Pattern: ([1-9][0-9]*|latest)

Required: Yes


The name of the project that contains the model that you want to start.

Length Constraints: Minimum length of 1. Maximum length of 255.

Pattern: [a-zA-Z0-9][a-zA-Z0-9_\-]*

Required: Yes

Request Body

The request accepts the following data in JSON format.


The maximum number of inference units to use for auto-scaling the model. If you don't specify a value, Amazon Lookout for Vision doesn't auto-scale the model.

Type: Integer

Valid Range: Minimum value of 1.

Required: No


The minimum number of inference units to use. A single inference unit represents 1 hour of processing. Use a higher number to increase the TPS throughput of your model. You are charged for the number of inference units that you use.

Type: Integer

Valid Range: Minimum value of 1.

Required: Yes

Response Syntax

HTTP/1.1 202 Content-type: application/json { "Status": "string" }

Response Elements

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

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


The current running status of the model.

Type: String



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


You are not authorized to perform the action.

HTTP Status Code: 403


The update or deletion of a resource caused an inconsistent state.

HTTP Status Code: 409


Amazon Lookout for Vision experienced a service issue. Try your call again.

HTTP Status Code: 500


The resource could not be found.

HTTP Status Code: 404


A service quota was exceeded the allowed limit. For more information, see Limits in Amazon Lookout for Vision in the Amazon Lookout for Vision Developer Guide.

HTTP Status Code: 402


Amazon Lookout for Vision is temporarily unable to process the request. Try your call again.

HTTP Status Code: 429


An input validation error occured. For example, invalid characters in a project name, or if a pagination token is invalid.

HTTP Status Code: 400

See Also

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