Forward Request from a Path to a Specific Port via .htaccess

Say you have a Node app running on port 3000, and you want yourdomain.com/app to route to it. With Apache, you can do this entirely through .htaccess using mod_rewrite and mod_proxy.

1. Enable the Modules

You need these three Apache modules:

sudo a2enmod rewrite
sudo a2enmod proxy
sudo a2enmod proxy_http
sudo systemctl restart apache2

2. The .htaccess Rule

Forward everything under /app to http://localhost:3000:

Options +FollowSymLinks -Indexes
IndexIgnore *
DirectoryIndex
<IfModule mod_rewrite.c>
  RewriteEngine on
  RewriteRule ^app/(.*)$ http://localhost:3000/$1 [P,L]
</IfModule>

Quick breakdown:

[P] — proxy mode (needs mod_proxy).
[L] — stop processing more rules if this one matches.
^app/(.*)$ — catches anything starting with /app/.

3. Good to Know

Make sure Apache is allowed to proxy to internal ports (check your security config).
If you’re using VirtualHost, put the rule there instead of .htaccess — better performance.
Want to forward the whole domain? Just drop the app/ part from the regex.

4. Multiple Apps, Multiple Ports

<IfModule mod_rewrite.c>
  RewriteEngine on
  RewriteRule ^app1/(.*)$ http://localhost:3001/$1 [P,L]
  RewriteRule ^app2/(.*)$ http://localhost:3002/$1 [P,L]
</IfModule>

After setting this up, hitting http://yourdomain.com/app forwards to whatever is running on localhost:3000.

References: