← ChatGPT & Codex changelog

OpenAI API — October, 2026

This release features prompt-to-voice capabilities for custom GPT-Live voice creation and an Ultrafast mode for GPT-6.1 Sol in the Responses API, delivering significant speed improvements. Additional major additions include a new Decisions API for 10x faster typed answers, native Decisions integration for GPT-Live, and nine new natural voices. API users also gain 12-hour prompt caching and simplified usage tiers, plus HIPAA compliance support for eligible organizations.

Source: official ChatGPT & Codex release notes. Summaries are written from the official notes; see how we work.

Added

  • Released prompt-to-voice for all API customers. Create a custom voice from a text description through the API or voice Playground, then reuse it in GPT-Live sessions. Creating a prompt-generated voice is free; speech generation uses regular GPT-Live session billing.
  • Added nine natural voices for GPT-Live: Nuri, Juni, and Flitz (German); Brise and Sillage (French); Nira (Hindi); Harema and Shida (Japanese); and Noeul (Korean).
  • Added native Decisions integration in GPT-Live. Your app can act while your user is speaking or react to what Live says. Let Live call Decisions directly through native delegation, or trigger decisions as input or output transcript deltas arrive.
  • 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

  • You can now choose 12-hour prompt caching in the API. 12-hour prompt caching keeps shared instructions, tools, and context cached longer to benefit from lower cached-input pricing, even when requests are hours apart. 12-hour cache writes cost 2.5x the input token price. Read more here.
  • 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.

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