Increased HTTP header size limit to 128 KB
We're excited to announce a significant increase in the maximum header size supported by Cloudflare's Content Delivery Network (CDN). Cloudflare now supports up to 128 KB for both request and response headers.
Previously, customers were limited to a total of 32 KB for request or response headers, with a maximum of 16 KB per individual header. Larger headers could cause requests to fail with HTTP 413
(Request Header Fields Too Large) errors.
- Support for large headers: You can now utilize much larger headers, whether as a single large header up to 128 KB or split over multiple headers.
- Reduces
413
and520
HTTP errors: This change drastically reduces the likelihood of customers encounteringHTTP 413
errors from large request headers orHTTP 520
errors caused by oversized response headers, improving the overall reliability of your web applications. - Enhanced functionality: This is especially beneficial for applications that rely on:
- A large number of cookies.
- Large Content-Security-Policy (CSP) response headers.
- Advanced use cases with Cloudflare Workers that generate large response headers.
This enhancement improves compatibility with Cloudflare's CDN, enabling more use cases that previously failed due to header size limits.
To learn more and get started, refer to the Cloudflare Fundamentals documentation.
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