TLS Reverse Proxy Configuration

When running LocalAI behind a TLS termination reverse proxy, the Web UI may fail to load static assets (CSS, JS) correctly because the application doesn't automatically detect that it's being served over HTTPS. This guide explains how to properly configure your reverse proxy to work with LocalAI.

How It Works

LocalAI uses the X-Forwarded-Proto HTTP header to determine the protocol used by clients. When this header is set to https, LocalAI will generate HTTPS URLs for static assets in the Web UI.

Running behind a reverse proxy (HTTPS / subpath)

LocalAI does not terminate TLS itself, so HTTPS is provided by a reverse proxy in front of it. Self-referential links (generated image and video URLs, async job status URLs, OAuth callbacks) need the externally visible scheme, host and port.

LocalAI determines these in this order:

1. LOCALAI_BASE_URL - if set, it is authoritative for the origin. Set it to the externally visible base URL, e.g. LOCALAI_BASE_URL=https://localai.example.com or https://192.168.0.13:34567. Recommended whenever links come back with the wrong scheme or host.
2. Otherwise, the X-Forwarded-Proto and X-Forwarded-Host headers (or the RFC 7239 Forwarded header) sent by the proxy. Ensure your proxy forwards X-Forwarded-Proto: https.

A reverse-proxy subpath mount is supported via X-Forwarded-Prefix; it is appended to LOCALAI_BASE_URL when both are present.

Required Headers

Your reverse proxy must forward these headers to LocalAI:

HAProxy Configuration

frontend https-in
    bind *:443 ssl crt /path/to/cert.pem
    mode http
    
    # Set the X-Forwarded-Proto header
    http-request set-header X-Forwarded-Proto https
    
    # Pass the original host
    http-request set-header X-Forwarded-Host %[hdr(host)]
    
    # If serving under a sub-path, set the prefix
    # http-request set-header X-Forwarded-Prefix /localai
    
    default_backend localai

backend localai
    mode http
    server localai1 127.0.0.1:8080 check

Apache Configuration

<VirtualHost *:443>
    ServerName your-domain.com
    SSLEngine on
    SSLCertificateFile /path/to/cert.pem
    SSLCertificateKeyFile /path/to/key.pem
    
    # Enable proxy and headers modules
    ProxyRequests Off
    ProxyPreserveHost On
    
    <Proxy *>
        Require all granted
    </Proxy>
    
    # Set the X-Forwarded-Proto header
    RequestHeader set X-Forwarded-Proto "https"
    
    # Set the X-Forwarded-Host header (optional, usually automatic)
    RequestHeader set X-Forwarded-Host "%{HTTP_HOST}s"
    
    # If serving under a sub-path
    # RequestHeader set X-Forwarded-Prefix "/localai"
    
    ProxyPass / http://127.0.0.1:8080/
    ProxyPassReverse / http://127.0.0.1:8080/
</VirtualHost>

Nginx Configuration

server {
    listen 443 ssl;
    server_name your-domain.com;
    
    ssl_certificate /path/to/cert.pem;
    ssl_certificate_key /path/to/key.pem;
    
    # Allow multimodal requests with images or other large inputs.
    client_max_body_size 50m;

    location / {
        proxy_pass http://127.0.0.1:8080;
        proxy_http_version 1.1;

        # Set the externally visible scheme and host.
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header Host $host;

        # If serving under a sub-path
        # proxy_set_header X-Forwarded-Prefix /localai;

        # Local inference can take much longer than common proxy defaults.
        proxy_connect_timeout 60s;
        proxy_send_timeout 60m;
        proxy_read_timeout 60m;

        # Stream responses as LocalAI emits them. Disabling request buffering is
        # optional and can help when clients upload large multimodal inputs.
        proxy_buffering off;
        proxy_request_buffering off;

        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_cache_bypass $http_upgrade;
    }
}

Adjust the 60m values for the slowest request you expect to serve. The important setting for long non-streaming requests is proxy_read_timeout: if the proxy stops waiting before LocalAI finishes, clients receive a proxy-generated 504 Gateway Time-out even though inference may still be running. OpenResty, Nginx Proxy Manager, Caddy, Traefik, HAProxy, and ingress controllers have equivalent upstream response timeout settings.

For bulk jobs on a trusted private network, you can also bypass the public reverse proxy and connect directly to LocalAI, for example http://localai-host:8080/v1.

Serving Under a Sub-Path

If you serve LocalAI under a sub-path (e.g., https://your-domain.com/localai), you need to:

1. Configure your reverse proxy to set the X-Forwarded-Prefix header

Example with Nginx:

proxy_set_header X-Forwarded-Prefix /localai;

Testing Your Configuration

1. Start LocalAI: localai
2. Configure your reverse proxy as shown above
3. Access the Web UI through the proxy
4. Check the browser's developer console for any mixed content warnings or failed asset loads
5. Verify that the HTML source contains https:// URLs for static assets

Troubleshooting

Static Assets Not Loading

• Verify the X-Forwarded-Proto header is being forwarded
• Check that the header value is exactly https (lowercase)
• Inspect the network tab in your browser to see which requests are failing

Mixed Content Warnings

• Ensure LocalAI is generating HTTPS URLs (check the BaseURL middleware is working)
• Verify the X-Forwarded-Proto header is set before LocalAI processes the request

Redirect Loops

• Check that your proxy is not adding duplicate headers
• Verify X-Forwarded-Proto is not being set to both http and https

504 Gateway Time-out During Inference

An HTML 504 Gateway Time-out page branded by Nginx or OpenResty means the reverse proxy stopped waiting for LocalAI. Increase the proxy's upstream read and send timeouts beyond the worst-case inference time. Also check its request body limit when sending images, audio, or other large inputs.

This is separate from LocalAI's optional busy watchdog. If busy watchdog checks are enabled, set LOCALAI_WATCHDOG_BUSY_TIMEOUT beyond the longest expected request or disable the busy check for workloads that legitimately run longer. The default busy timeout is 5 minutes, but it is only enforced when the busy watchdog is enabled.

Security Note

When using reverse proxies, ensure your proxy only accepts connections from trusted sources and properly validates SSL certificates. Never expose LocalAI directly to the internet without TLS termination.