← ChatGPT & Codex changelog

OpenAI API — October, 2026

This release introduces new models, GPT-6 Rosalind for biological reasoning and GPT-6.1 Terra for visual tasks and efficient writing, alongside exciting new capabilities like prompt-to-voice for custom voice creation and Ultrafast modes across Agents and Responses APIs for reduced latency. The Decisions API is now generally available with increased question limits, and eligible ChatGPT Pro and Business subscribers can claim monthly API credits. Further enhancements include 12-hour prompt caching, improved Agents API sandboxes with new SDKs and billing only for active turns, simplified API usage tiers, and integrated HIPAA compliance support for organizations.

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

Added

  • Released GPT-6 Rosalind, bringing specialized biological reasoning with scientific tool use to complex life sciences research. Access is available to organizations approved for Rosalind Research through the trusted-access program for internal research by authorized users.
  • Released GPT-6.1 Terra, a fast, efficient model for visual reasoning, precise computer use, and clear, natural writing.
  • 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 Ultrafast mode to the Agents API. Set agent.service_tier to ultrafast with a supported model to reduce the time between generated tokens.
  • 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

  • Eligible ChatGPT Pro and Business subscribers can now claim up to $500 per month in free API credits as a subscription benefit. Activate the benefit from ChatGPT or API Platform by linking an API organization you own. See API credits for ChatGPT subscribers for credit amounts, eligibility, and how to claim.
  • See the GPT-6 guide for prompting and migration guidance.
  • The Decisions API is now generally available with gpt-6-luna. Cache shared input across requests for prompt-cache discounts, include images in individual question instructions, and pass structured data directly with input_json. Each request now supports up to 400 questions, increased from 200 in public beta. Review the changes since public beta.
  • You can now choose which service tiers projects can use in Platform settings. Organization settings can restrict service tiers for all projects. See service tier errors.
  • 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.
  • OpenAI-hosted sandboxes in the Agents API now include the Artifact SDK and skills for creating and editing spreadsheets, presentations, and Word documents.
  • You can now pre-warm an OpenAI-hosted sandbox before attaching it to an Agents API session. Prewarming improves latency by creating and configuring the sandbox before a user finishes sending their message. This means the user doesn't have to wait for all this work to complete.
  • OpenAI-hosted sandbox compute is now billed during active turns. You no longer pay for idle time between turns.
  • 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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