How to Get Visitor’s IP Address in Nginx and Express.js Application

Activating the forwarding of IP addresses requires some configuration on your server. This tutorial shows you how to obtain a visitor’s IP address in 3 simple steps.

Express App Behind Proxies

When running an Express app behind a proxy, you have to set the application variable trust proxy to true. Express offers a few other trust proxy values which you can review in their documentation, but for now, we don’t have to mind them.

Without further ado, these are the steps to reveal a visitor’s IP address to your app:

1. app.set('trust proxy', true) in your Express app.
2. Add proxy_set_header X-Forwarded-For $remote_addr in the Nginx configuration for your server block.
3. You can now read off the client’s IP address from the req.ip property.