Wirestack
Fast mode for Claude Opus 5.5 leaves research preview on October 15, 2026: no beta header, $8 input and $40 output
Opus 5.5 fast mode needs no beta header or access request from Oct 15, 2026. Set speed fast; $8 in, $40 out per 1M tokens.
Your keys
0 of 1 ready
Create each key on its own page, paste it below, then copy the finished lines into your project's .env file. What you paste stays in this tab. It is never sent to Wirestack or saved.
- Anthropic API keyANTHROPIC_API_KEYGet key
Click Create key. It starts with sk-ant- and is shown only once
What you get
On October 15, 2026 Anthropic moved fast mode for Claude Opus 5.5 (claude-opus-5-5) out of research preview. You no longer need to request access or send the fast-mode-2026-02-01 beta header. Opus 5.5 now has a default fast mode rate limit in the Start, Build and Scale usage tiers.
The guide says fast mode gives up to 2.5x higher output tokens per second at premium pricing. You opt in with speed: "fast". Opus 5.5 fast mode costs $8 per million input tokens and $40 per million output tokens. Prompt caching and data residency multipliers apply on top.
Fast mode for Claude Opus 5 and Claude Opus 4.8 stays in research preview and still needs the beta header.
Prerequisites
- An Anthropic API key in
ANTHROPIC_API_KEY - An organization in the Start, Build or Scale tier
- An app calling
claude-opus-5-5
Steps
- Add
speed: "fast"to Opus 5.5 requests where output speed matters, following the official guide. - Handle
429errors, or fall back to standard speed. The guide says the fallback causes a prompt cache miss. - Keep it out of Batch API jobs and Priority Tier traffic, where it is not available.
Test it
Send one request with speed: "fast" and check that usage.speed in the response is "fast".
Not confirmed
- The exact default fast mode rate limits for each tier.
- When fast mode for Opus 5 and Opus 4.8 will leave research preview.