413 Content Too Large means the server refuses the request because its content (the request body) is larger than the server is willing or able to process. RFC 9110 gave the code its current name; older specifications called it "Request Entity Too Large" (RFC 2616) and "Payload Too Large" (RFC 7231), and many servers still send those reason phrases.
The server may close the connection to stop the client from sending the rest of the body. If the condition is temporary, it should send Retry-After. Clients that send Expect: 100-continue can learn about the limit before they upload anything.
Common limits are nginx's client_max_body_size (1 MB by default), PHP's upload_max_filesize and post_max_size, and the request size caps of many proxies and serverless platforms.
Example response
HTTP/1.1 413 Content Too Large
Date: Fri, 06 Nov 2026 10:15:32 GMT
Connection: close
Content-Type: application/json
Content-Length: 40
{"error":"Uploads are limited to 10 MB"}SEO and redirect checking
Crawlers send no request bodies, so 413 has no SEO impact. TrueURL limits the size of POST bodies; a 413 from the target means its own limit is smaller than the body you sent.
Common causes and use cases
- An image or video upload exceeds the server's maximum (
client_max_body_sizein nginx,LimitRequestBodyin Apache). - PHP's
upload_max_filesizeorpost_max_sizeis lower than the size of the uploaded file. - An API request contains far more data than expected, such as files encoded as base64 inside JSON.