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v1

latestOpenAPI 3.0.0Apache 2.0 License2026-07-14108906717.7 KB

Creates a fine-tuning job to customize a base model.

You specify the base foundation model and the location of the training data. After the model-customization job completes successfully, your custom model resource will be ready to use. Amazon Bedrock returns validation loss metrics and output generations after the job completes.

For information on the format of training and validation data, see Prepare the datasets.

Model-customization jobs are asynchronous and the completion time depends on the base model and the training/validation data size. To monitor a job, use the GetModelCustomizationJob operation to retrieve the job status.

For more information, see Custom models in the Amazon Bedrock User Guide.

post/model-customization-jobs

Request body

jobNamestring required

A name for the fine-tuning job.

customModelNamestring required

A name for the resulting custom model.

roleArnstring required

The Amazon Resource Name (ARN) of an IAM service role that Amazon Bedrock can assume to perform tasks on your behalf. For example, during model training, Amazon Bedrock needs your permission to read input data from an S3 bucket, write model artifacts to an S3 bucket. To pass this role to Amazon Bedrock, the caller of this API must have the <code>iam:PassRole</code> permission.

clientRequestTokenstring

A unique, case-sensitive identifier to ensure that the API request completes no more than one time. If this token matches a previous request, Amazon Bedrock ignores the request, but does not return an error. For more information, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/APIReference/Run_Instance_Idempotency.html">Ensuring idempotency</a>.

baseModelIdentifierstring required

Name of the base model.

customizationType'FINE_TUNING' | 'CONTINUED_PRE_TRAINING' | 'DISTILLATION' | 'REINFORCEMENT_FINE_TUNING' | 'IMPORTED'

The customization type.

customModelKmsKeyIdstring

The custom model is encrypted at rest using this key.

hyperParametersobject

Parameters related to tuning the model. For details on the format for different models, see <a href="https://docs.aws.amazon.com/bedrock/latest/userguide/custom-models-hp.html">Custom model hyperparameters</a>.

Response

Success

jobArnstring required

Amazon Resource Name (ARN) of the fine tuning job