Nginx '413 Request Entity Too Large' on file uploads: how do I raise client_max_body_size correctly?

Cause: nginx limits the size of a client request body. The default for client_max_body_size is 1m. When a request body is larger, nginx answers 413 (Request Entity Too Large) before your application sees it. Browsers may not display this error well, so uploads often just seem to fail. Fix: 1. Set the directive in the narrowest place that needs it. It is allowed in http, server and location. For example, inside the server block for your site: client_max_body_size 20m; or only in the upload location with a bigger value such as 100m. 2. Run nginx -t, then reload nginx (nginx -s reload or systemctl reload nginx). 3. If another proxy sits in front (a load balancer, ingress controller or CDN), it has its own body limit; raise it there too. The application framework may also have an upload limit that you must raise separately. 4. Pick a realistic maximum. Setting 0 turns the check off entirely, which lets any client push unlimited data at your server; avoid that on public endpoints. Verify: upload a file just under the new limit and it succeeds; a file over the limit still gets 413 (confirming the limit is what you set). Sources: https://nginx.org/en/docs/http/ngx_http_core_module.html https://nginx.org/en/docs/http/ngx_http_proxy_module.html