OpenAI adds Ultrafast mode for GPT-6 Astra in the Responses API

ChatGPTProduct changeConfirmed

OpenAI added Ultrafast mode for GPT-6 Astra in the Responses API.

Developers use the gpt-6-astra model with service_tier set to "ultrafast" to reduce the time between generated output tokens.
OpenAI links separate Ultrafast pricing, which this entry does not restate.

Who can use it: API customers, subject to rate limits. Processing is global with US data residency; EU and other regional inference residency are not supported.
When: Listed in the OpenAI API changelog on September 29, 2026.

OpenAI API changelog Announced 2026-09-29 · date only

Read the official announcement for access details. Availability can depend on your plan, region or workplace settings.

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