Claude Opus 5.5 fast mode leaves research preview
Fast mode for Claude Opus 5.5 no longer requires an access request or beta header. It is also now available through Microsoft Foundry for Azure-hosted deployments.
What changed
Opus 5.5 fast mode is out of research preview. Start, Build and Scale usage tiers now have a default fast mode rate limit. Requests that still send the earlier beta header continue to work.
Why it may matter for your work
Teams could adopt fast mode without waiting for access approval. Azure-based developers may also gain another deployment option for applications where response time matters.
What it can actually do
Use Opus 5.5 fast mode without requesting access, including on Azure-hosted Microsoft Foundry deployments.
Limits to check
The page does not state prices, speed measurements or numerical rate limits. Fast mode for Opus 5 and Opus 4.8 remains in research preview and still requires the beta header.
“Claude Opus 5.5 now has a default fast mode rate limit in the Start, Build, and Scale usage tiers.”From the linked source page