Reinforcement fine-tuning on Amazon Bedrock with OpenAI-Compatible APIs: a technical walkthrough

Amazon AWS AI Blog / 3/26/2026

💬 OpinionDeveloper Stack & InfrastructureTools & Practical Usage

Key Points

  • The article provides an end-to-end technical walkthrough for running reinforcement fine-tuning (RFT) on Amazon Bedrock using OpenAI-compatible APIs, starting with authentication setup.
  • It explains how to deploy a Lambda-based reward function that Bedrock uses during RFT.
  • The guide covers how to start a reinforcement training job and manage the workflow for subsequent on-demand inference using the fine-tuned model.
  • It focuses on implementation details across multiple components (Bedrock, OpenAI-compatible request patterns, and AWS Lambda) to help teams reproduce the pipeline.
In this post, we walk through the end-to-end workflow of using RFT on Amazon Bedrock with OpenAI-compatible APIs: from setting up authentication, to deploying a Lambda-based reward function, to kicking off a training job and running on-demand inference on your fine-tuned model.