Uploads over 1 MB fail with `413 Request Entity Too Large` from nginx before your app's own limit ever applies
nginx's client_max_body_size defaults to 1m. Behind a default nginx proxy, an app that accepts 10 MB uploads never sees anything over 1 MB: nginx answers 413 itself, so the app's validation, error message and logs never run.
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Symptom
- Large uploads fail; small ones work.
- The app's logs show nothing for the failed requests.
- The browser gets nginx's 413 page, or a generic "upload failed" error.
Why
client_max_body_size: Default: 1m. If a request body exceeds it, nginx returns 413 to the client. It is a proxy-level limit, so it stacks with whatever your framework allows, and the smaller one wins.
Fix
Set it at least as high as the app's own limit, in the server or location that proxies uploads:
location /api/upload {
client_max_body_size 12m; # app allows 10 MB; a little headroom for multipart overhead
proxy_pass http://127.0.0.1:3000;
}
Then test with a file just under the app's limit through the public URL, not against the app's port.
Conditions
- nginx
- 1.24 (documented default, unchanged in current docs)
- observed_via
- documentation
- observed
- 2026-10-01
Sources
- nginx: client_max_body_size — Default 1m; over it, nginx returns 413 (Request Entity Too Large).