---
title: How to enable CORS in Nginx for an Elixir Phoenix app?
date: '2023-01-30T00:00:00+00:00'
url: https://www.abhinav.co/enable-cors-for-nginx-reverse-proxy
summary: If you use Nginx as a proxy for your Phoenix app, here is the configuration
  that you can use
tags:
- Elixir
- Phoenix
- Nginx
- CORS
author: Abhinav Saxena
---

# How to enable CORS in Nginx for an Elixir Phoenix app?

I use Nginx as a proxy for my Elixir Phoenix app. Last week, I spent more than a day to figure out right configuration to enable CORS. This was in addition to using `cors-plug` Plug in the app.

If the URL is `example.com` and Phoenix app runs on the port `4000`, you can create a configurtion file `/etc/nginx/sites-enabled/example.com` and add following configuration:

```lua
server {
  listen 80;
  server_name example.com www.example.com;

  add_header 'Access-Control-Allow-Credentials' 'true';

  location / {
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://localhost:4000;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_hide_header Access-Control-Allow-Origin;
    add_header Access-Control-Allow-Origin "$http_origin" always;
  }
```

(I tried almost all configurations available on StackOverflow and the one on [enable cors](https://enable-cors.org/server_nginx.html) website, but none of them worked for me.)