What changed
ClaudeDevs said the maximum request size for Messages and Token Counting rose from 32 MB to 128 MB. The API overview lists those two endpoints at 128 MB on the first-party Claude API. It does not record the old 32 MB figure or a change date, so the raise itself is the post's account. The post time is 2026-10-29T21:49:21Z.
ClaudeDevs said long computer-use sessions and big PDFs were hitting 32 MB with plenty of context window left, and described the new room as about four times larger. That comparison is the account's own description of the cap it says replaced 32 MB. For requests with more than 20 images, ClaudeDevs said the per-image limit rose from 2000 px to 3000 px. The request-size section does not document pixel size.
Other caps on that page are listed below. The post does not say they moved. Over a listed first-party limit, the API returns a 413 request_too_large error.
| Endpoint | Maximum request size |
|---|---|
| Messages, Token Counting | 128 MB |
| Message Batches API | 256 MB |
| Files API | 500 MB |
| Sessions, Agents, Environments | 32 MB |
Who it is for
The 128 MB cap is for callers of the first-party API at https://api.anthropic.com. Messages is POST /v1/messages. Token Counting, POST /v1/messages/count_tokens, counts tokens in a message before sending. Sessions, Agents, and Environments are listed as beta, with a 32 MB request cap.
You need a Claude Console account and either a Console API key or a configured Workload Identity Federation rule. The post and the request-size section state no price, discount, plan requirement, or regional rollout.
ClaudeDevs limited 128 MB to the first-party API and put cloud platforms between 20 MB and 32 MB. The overview names the hosts: Amazon Bedrock at 20 MB; Claude Models on Google Cloud (Google managed) at 30 MB; and Messages and Token Counting up to 32 MB on Claude Platform on AWS, Claude Models on Google Cloud (Anthropic managed), and Microsoft Foundry. It tells you to consult each platform's documentation for current values.
How to try it
Send the same POST /v1/messages or POST /v1/messages/count_tokens request. The post adds no endpoint. It links the request-size section. The overview says you can try the API in the Console playground and create keys on the API keys page. SDKs send authentication, anthropic-version, and content-type. A direct call needs content-type application/json and anthropic-version. The authentication table's example version is 2026-10-21. Over the first-party size limit, the documented error is 413 request_too_large.
What is still unclear
The overview does not date the cap. The sample anthropic-version 2026-10-21 is only an authentication example. Pixels, the old 32 MB figure, and any price for the larger body are outside that page.
Source
Also from
Sources and editorial approach
This brief uses the ClaudeDevs post of 29 October 2026 and the Claude API overview on platform.claude.com, read the same day. Current size caps, the 413 error, endpoint paths, and cloud-host limits are from that overview. The old 32 MB cap, the four-times wording, the computer-use and PDF explanation, and the 2000-to-3000 px rule are from ClaudeDevs. The overview does not date the change. Claude Code release notes were not a source for this limit.