File uploads

Open Forms supports file upload fields in forms, which needs some special care at the webserver level.

Typically Open Forms is deployed behind a load balancer - on Kubernetes this would be your ingress solution, while on a single-server setup you’d typically run a reverse proxy like nginx on your host.

Misconfiguration or bad tuning will typically result in HTTP 413 Request Entity Too Large errors.

Endpoints

The following endpoint(s) process file-uploads:

• /api/v1/submissions/files/upload

We recommend specifying upload limits specifically for these endpoints, as allowing large requests bodies poses a Denial-of-Service (DOS) risk.

For example:

location = /api/v1/submissions/files/upload {
    client_max_body_size 50M;

    // usual proxy directives...
    proxy_pass http://backend;
}

Environment variable

Additionally, Open Forms supports the MAX_FILE_UPLOAD_SIZE environment variable. File uploads larger than that will be rejected, and the value will be dynamically presented in the form designer and relevant API documentation.