Changelog

Responses API support

December 9, 2025

You can now use OpenAI’s latest Responses API inside LangFast.

Responses API support

What’s new

  • Full support for the Responses API
  • Compare prompt outputs side-by-side
  • Debug the exact setup you’ll ship

How it works

  • Select the Responses provider in your prompt setup
  • Run tests, compare outputs, and validate reliability before shipping to production
Ship prompts that pass the tests
Don't wait until they break in production
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