Claude API Raises the Max Request Size From 32 MB to 128 MB, Giving About 4x More Room for Images and PDFs

Anthropic has raised the maximum request size for the Messages API and the Token Counting API on the Claude API from 32 MB to 128 MB, about 4x more room.

The reason Anthropic gives: image-heavy requests, such as long computer use sessions and big PDFs, were hitting the 32 MB cap with plenty of context window left.

The frame above is from the announcement video. Each image is 0.5 MB and uses 4,784 tokens. At 37 MB of images, the request is already past the old 32 MB cap while using only 36% of a 1M-token context.

Max request size by endpoint

According to the Claude API documentation, the request size limits on the Claude API are now:

Endpoint	Max request size
Messages, Token Counting	128 MB (was 32 MB)
Message Batches API	256 MB
Files API	500 MB
Sessions, Agents, Environments	32 MB

Requests over these limits get a 413 request_too_large error.

First-party Claude API only

The 128 MB limit applies only to the Claude API called directly through Anthropic. Through cloud platforms, the limit is still between 20 and 32 MB.

Platform	Max request size
Amazon Bedrock	20 MB
Claude Models on Google Cloud (Google managed)	30 MB
Claude Platform on AWS, Claude Models on Google Cloud (Anthropic managed), Microsoft Foundry	32 MB

Larger images in requests with more than 20 images

Anthropic has also raised the per-image limit for requests with more than 20 images, from 2,000 px to 3,000 px on each side.

Worth knowing, from the Vision documentation:

• Every image in the request counts, including images from earlier turns that you resend and screenshots returned in a computer use tool_result
• With 20 or fewer images, each image can be up to 8,000 x 8,000 px
• The API accepts up to 600 images per request for most models, and 100 for models with a 200k-token context window, but the request size limit may be reached first
• Each image on the Claude API can be up to 10 MB base64-encoded

Who benefits

• Long computer use and browser use sessions that send a screenshot back at every step, the work most likely to hit 32 MB. See also the computer use toolset in the Claude SDK
• Large PDFs and multi-page scanned documents
• Analysis of many images in a single request

For very large images or files, Anthropic recommends uploading through the Files API and referencing them by file_id instead of attaching base64 every time. In multi-turn work, each request resends the full conversation history, including any base64 images.