The Claude API gives access to Anthropic's Claude models through the Messages API. Supports chat, vision, tool use, streaming, adaptive thinking, prompt caching and batch processing; SDKs for Python, TypeScript, Go, Java, C#, PHP and Ruby.
You can now host the Managed Agents API, agent loop and session storage yourself. Same API, but no Messages or Files API.
claude-fable-5-2 costs $8 / $40 per million tokens, down from $10 / $50. Edited history, old computer use and 5.1 advisors now return 400.
Text from Claude Mythos 5, Claude Opus 4.7 and Claude Sonnet 4.6 carries a watermark. No code change; on Sonnet 4.6 skip sampling params.
Python 2.5.0 and TS 1.5.0 add error classes and error code fields. In Python, OverloadedError now counts as an InternalServerError.
Claude Enterprise admins get a beta endpoint that ends a member's sessions, trusted devices and org OAuth tokens. SDKs added it today.
Admins can now limit Claude API and Console access to listed IP ranges, so a leaked API key is much harder to use elsewhere.
The Messages API can now keep a conversation on the server, so long chats and agent loops send smaller requests and answer faster.
From Nov 30, 2026, Claude Opus 4.8 requests with speed "fast" return an error. Move fast mode traffic to Claude Opus 5.5.
Messages and Token Counting requests can now be up to 128 MB on the first-party Claude API. Bedrock and other clouds keep lower limits.
New SDKs send API version 2026-10-21: temperature, top_p and top_k now return a 400, keys go in Authorization: Bearer.
New /v1/user_profiles endpoints let platforms tag requests by end customer, so enforcement hits one profile, not the whole org.
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.
Wirestack