OpenAI ships Ultrafast mode for GPT-6.1 Sol in the API, Codex and ChatGPT Work
Confirmed
The takeaway
On Oct 8, 2026, nine days after promising it “in the coming days”, OpenAI made its Ultrafast service tier available for GPT-6.1 Sol to all API users (service_tier “ultrafast” in the Responses API) and in Codex and ChatGPT Work for Pro $500 and eligible Enterprise and Edu plans.
Status
- Claim
Confirmed
- Our reporting
- High confidence
- Importance
- 3 of 5
- Last verified
- 8 October 2026
Your AI and this story
- GPT-6 Astra161 days after its cutoff
- Claude Opus 5.5100 days after its cutoff
- Gemini 3.8 Flash191 days after its cutoff
- Grok 4.7130 days after its cutoff
None of these four assistants can know about it. The closest, Claude Opus 5.5, stops 100 days before it.
Key facts
- API changelog (Oct 8): ‘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.’ Available to all API users subject to rate limits, with global processing and US and EU data residency
- Pricing (per 1M tokens, short context): $12 input, $0.60 cached input, $15 cache writes, $60 output, 6x the standard $2/$0.10/$2.50/$10; long context $24/$1.20/$30/$90. GPT-6 Astra Ultrafast is $60/$300 (OpenAI pricing page)
- Ultrafast has separate rate limits from Standard and Fast; OpenAI strongly recommends WebSockets for agentic use (Ultrafast guide)
- Codex and ChatGPT Work (Codex changelog, Oct 8): available on Pro $500 and eligible Enterprise and Edu plans; Enterprise access is off by default and must be enabled by workspace owners; US and Europe inference residency
- At GPT-6.1 Sol’s Sept 29 launch OpenAI promised up to 8x faster token generation in Codex and up to 6x via the API (OpenAI; third-party summaries cite up to ~300 tokens/s)
What happened
OpenAI introduced Ultrafast as a premium inference tier with GPT-6 Astra and promised a GPT-6.1 Sol version at DevDay (Sept 29). It shipped on Oct 8 in both the API and Codex/ChatGPT Work. In the API anyone can use it; in Codex it is limited to the $500 Pro plan and enterprise and education workspaces that enable it.
Why it matters
Speed is becoming a priced product dimension: the same model now comes in Standard, Fast (2x) and Ultrafast (6x) tiers. For agentic coding, where runs take many sequential tool calls, faster token generation shortens wall-clock time, which OpenAI sells at a premium on its top plan.
Sources
5 sources from 2 sites. Numbers match the chips in the text.
5 sources: 5 primary
Primary
- OpenAI API changelog (Oct 8: Ultrafast for GPT-6.1 Sol)developers.openai.com, docs
- OpenAI docs: Ultrafast modedevelopers.openai.com, docs
- OpenAI API pricing (Ultrafast tab)developers.openai.com, docs
- Codex changelog (Oct 8: GPT-6.1 Sol Ultrafast in Codex and ChatGPT Work)developers.openai.com, docs
- OpenAI: Introducing GPT-6.1 Sol (Sept 29)openai.com, official
Changes
- Filed (outcome of upcoming item GPT-6.1 Sol Ultrafast (up to 8x faster in Codex) promised ‘in the coming days’; API and Codex changelogs, pricing page and guide read)