← ChatGPT & Codex changelog

OpenAI API — October, 2026

This release introduces significant speed enhancements and new capabilities for developers. Key additions include Ultrafast mode for GPT-6.1 Sol, drastically reducing output token generation time, and the beta Decisions API with gpt-6-luna for 10x faster text and image-to-answer conversions. Additionally, a new in-product flow for HIPAA compliance support simplifies BAA acceptance for eligible organizations. API usage tiers are also streamlined from five to three for clearer understanding of monthly limits and automatic upgrades.

Added

  • Added Ultrafast mode for GPT-6.1 Sol in the Responses API. Use gpt-6.1-sol with service_tier: "ultrafast" to reduce the time between generated output tokens. It is available to all API users, subject to rate limits, with global processing and US and EU data residency. See Ultrafast pricing.
  • Released the Decisions API in beta with gpt-6-luna. Turn text and images into typed answers 10x faster than the Responses API.
  • Added an in-product flow for HIPAA compliance support in API Organization settings > General. Admins of eligible organizations can now accept the standard Business Associate Agreement (BAA) and enable HIPAA compliance support for their organization. See the Help Center for eligibility, covered services, and configuration requirements.

Changed

  • Updated the chat-latest snapshot, which points to the latest model available in ChatGPT for Plus, Pro, Business and Enterprise users. We recommend leveraging the GPT-6 model family for production API usage, but feel free to use this model to test the latest improvements for chat use cases. The underlying model snapshot will be regularly updated. Read more here.
  • Simplified API usage tiers from five to three: Build, Launch, and Grow. Organizations automatically upgrade as total credit purchases reach tier minimums. See usage tiers for monthly usage limits and how to view rate limits for each model.