nginx.conf

events {
    worker_connections 1024;
}

http {
    upstream api {
        server api:8000;
    }

    server {
        listen 80;
        server_name localhost;

        # CORS settings
        set $cors_credentials 'true';
        set $cors_content_type '';
        set $cors_content_length '';

        if ($http_origin ~ '.+') {
            set $cors_credentials 'true';
        }

        if ($request_method = OPTIONS) {
            set $cors_content_type 'text/plain';
            set $cors_content_length '0';
        }

        # CORS headers
        add_header Access-Control-Allow-Origin $http_origin always;
        add_header Access-Control-Allow-Credentials $cors_credentials always;
        add_header Access-Control-Allow-Methods "GET, POST" always;
        add_header Access-Control-Allow-Headers "DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Signature,Account-Id" always;

        # Handle preflight requests
        if ($request_method = OPTIONS) {
            return 204;
        }

        location / {
            proxy_pass http://api;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
        }
    }
}