OpenAI appears to be preparing a wider rollout of its Ultrafast API mode timed to DevDay on September 29, TestingCatalog reported, with new references appearing across OpenAI's Platform and API documentation. A hidden speed selector is being built for the Responses API Playground that would let developers choose between Standard, Fast, and Ultrafast processing.

OpenAI has already previewed Ultrafast with GPT-5.6 Sol, claiming up to 750 output tokens per second and up to 14 times faster inference than Standard. Access remains limited to select customers, and OpenAI confirmed the mode is powered by Cerebras hardware. References to "Ultrafast" just appeared in the cloud-agent API docs, spotted by the X account imjustnewatai on September 26.

With the GPT-6 family now released, whether Sol, Luna, and Astra get Ultrafast support is the open question. The real trade-off for developers will likely be economics: paying more for latency only where response time directly affects revenue. It fits a broader DevDay infrastructure story, alongside new Platform onboarding tiers like "Accelerate" for production workloads.