PHP-FPM with NGINX is the standard way to run PHP on Nginx. Nginx has no built-in PHP module like Apache’s mod_php. Nginx serves static files and forwards .php requests to PHP-FPM over FastCGI, usually through a Unix socket.

In this tutorial you install PHP-FPM on Ubuntu, create a dedicated pool, connect Nginx with fastcgi_pass, test the stack, and troubleshoot 502 errors.

Version note: Commands were checked against Ubuntu 22.04 LTS (Jammy), 24.04 LTS (Noble Numbat), and 26.04 LTS (Resolute Raccoon) with PHP from the default Ubuntu repositories. Default PHP versions per release: 8.1 on 22.04, 8.3 on 24.04, and 8.5 on 26.04. Confirm your host with lsb_release -rs and php -v before you edit paths or service names.

Use this table to swap package names, sockets, and config paths on your server. Default PHP versions come from the Ubuntu archive. See php-fpm on Noble (24.04) and php-fpm on Resolute (26.04).

Pool configs live under /etc/php/<version>/fpm/pool.d/. On 24.04 and 26.04, sudo apt install php-fpm installs the default metapackage for that release.

The step-by-step examples below use PHP 8.1 on Ubuntu 22.04. Replace 8.1 with 8.3 or 8.5 when you work on 24.04 or 26.04.

• Nginx does not execute PHP. PHP-FPM runs worker processes and receives requests through FastCGI.
• Install the FPM package for your PHP version: php8.1-fpm on 22.04, php8.3-fpm on 24.04, or php8.5-fpm on 26.04.
• Point Nginx at the pool socket with fastcgi_pass unix:/run/php/php8.1-fpm.sock (swap 8.1 for 8.3 or 8.5 as needed) inside a location ~ \.php$ block.
• Pool files live in /etc/php/<version>/fpm/pool.d/. Each [pool_name] section controls user, socket path, and process manager settings.
• A 502 Bad Gateway usually means a socket mismatch, stopped PHP-FPM service, or wrong file permissions on the socket.
• Unix sockets work for Nginx and PHP-FPM on the same server. TCP port 9000 fits containers or remote FPM hosts.
• Separate pools let you run different sites under different Unix users and PHP versions.

Before you start, confirm you have:

• An Ubuntu 22.04, 24.04, or 26.04 LTS server with SSH access as a sudo-enabled user.
• Nginx installed. On 22.04, follow How To Install Nginx on Ubuntu 22.04. On 24.04 or 26.04, run sudo apt install nginx after sudo apt update.
• PHP installed, or plan to install the LEMP stack. The full 22.04 walkthrough is How To Install Linux, Nginx, MySQL, PHP (LEMP stack) on Ubuntu 22.04. The same package names apply on newer LTS releases when you use the version table above.

PHP-FPM (FastCGI Process Manager) is a PHP SAPI that manages a pool of worker processes. A master process listens on a socket or TCP port. Worker processes execute PHP scripts and return output to the web server.

PHP-FPM vs mod_php

1. A browser requests https://example.com/index.php.
2. Nginx matches location ~ \.php$ and passes the request to PHP-FPM through FastCGI.
3. PHP-FPM assigns an idle worker or spawns one based on pool settings.
4. The worker runs the script and sends the response back to Nginx.
5. Nginx returns the response to the client.

For the official Nginx integration notes, see Nginx on Unix systems.

Check your Ubuntu and PHP versions:

lsb_release -rs
php -v

Install the FPM package that matches your release:

On 24.04 and 26.04 you also have the option to run sudo apt install php-fpm, which installs the default PHP FPM metapackage for that release.

The 22.04 example continues below:

sudo apt update
sudo apt install php8.1-fpm

Enable and start the service. Swap the service name on 24.04 (php8.3-fpm) or 26.04 (php8.5-fpm):

sudo systemctl enable php8.1-fpm
sudo systemctl start php8.1-fpm
sudo systemctl status php8.1-fpm

You should see active (running). Confirm the default socket:

ls -l /run/php/php8.1-fpm.sock

Expected socket paths by release:

The default pool file is /etc/php/8.1/fpm/pool.d/www.conf on Ubuntu 22.04. On 24.04 use /etc/php/8.3/fpm/pool.d/www.conf. On 26.04 use /etc/php/8.5/fpm/pool.d/www.conf. For a single site, editing www is enough. For multiple apps, create one pool per site.

This example creates a pool named wordpress_site under a dedicated user.

Create the user and group:

sudo groupadd wordpress_user
sudo useradd -g wordpress_user -d /var/www/wordpress -s /usr/sbin/nologin wordpress_user

Create the pool file:

sudo nano /etc/php/8.1/fpm/pool.d/wordpress_pool.conf

Add the following configuration. Keep the PHP version consistent in the socket path:

[wordpress_site]
user = wordpress_user
group = wordpress_user
listen = /run/php/php8.1-fpm-wordpress.sock
listen.owner = www-data
listen.group = www-data
listen.mode = 0660

php_admin_value[disable_functions] = exec,passthru,shell_exec,system
php_admin_flag[allow_url_fopen] = off

pm = dynamic
pm.max_children = 20
pm.start_servers = 4
pm.min_spare_servers = 2
pm.max_spare_servers = 8
pm.max_requests = 500

Pool directives explained:

Reload PHP-FPM after changes. Use the service name for your PHP version:

sudo systemctl reload php8.1-fpm

On 24.04 run sudo systemctl reload php8.3-fpm. On 26.04 run sudo systemctl reload php8.5-fpm.

Verify the new socket exists:

ls -l /run/php/php8.1-fpm-wordpress.sock

Create or edit a server block in /etc/nginx/sites-available/. Point fastcgi_pass at the pool socket from Step 2.

server {
    listen 80;
    server_name example.com;
    root /var/www/wordpress;
    index index.php index.html;

    access_log /var/log/nginx/example.com-access.log;
    error_log  /var/log/nginx/example.com-error.log;

    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/run/php/php8.1-fpm-wordpress.sock;
    }

    location ~ /\.ht {
        deny all;
    }
}

snippets/fastcgi-php.conf ships with the Ubuntu Nginx package. It sets fastcgi_split_path_info and SCRIPT_FILENAME using $document_root$fastcgi_script_name.

Enable the site and test the config:

sudo ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl reload nginx

Set ownership on the web root so the pool user reads the files:

sudo chown -R wordpress_user:wordpress_user /var/www/wordpress

For Nginx troubleshooting patterns, see Nginx Essentials.

Create a test file in the web root:

echo '<?php phpinfo(); ?>' | sudo tee /var/www/wordpress/info.php

Open http://example.com/info.php in a browser. Confirm $_SERVER['USER'] shows wordpress_user, which means Nginx routed the request through your custom pool.

Delete info.php after testing. phpinfo() exposes server details to anyone who visits the URL.

sudo rm /var/www/wordpress/info.php

On 24.04 use unix:/run/php/php8.3-fpm.sock. On 26.04 use unix:/run/php/php8.5-fpm.sock.

Socket example (default pool):

fastcgi_pass unix:/run/php/php8.1-fpm.sock;

TCP example (set listen = 127.0.0.1:9000 in the pool file first):

fastcgi_pass 127.0.0.1:9000;

Nginx returns 502 Bad Gateway when PHP-FPM is unreachable or fails to respond. Work through these checks in order.

1. Confirm PHP-FPM is running. On 22.04:

sudo systemctl status php8.1-fpm

On 24.04 check php8.3-fpm. On 26.04 check php8.5-fpm.

2. Match the socket path in Nginx and the pool listen directive. Swap 8.1 for your PHP version:

grep -r fastcgi_pass /etc/nginx/sites-enabled/
grep listen /etc/php/8.1/fpm/pool.d/*.conf

3. Check socket permissions. Nginx runs as www-data and needs read/write access to the socket:

ls -l /run/php/

4. Read the logs:

sudo tail -f /var/log/nginx/error.log
sudo journalctl -u php8.1-fpm -f

On 24.04 replace the unit with php8.3-fpm. On 26.04 use php8.5-fpm.

5. Raise timeouts if scripts run long. Add inside the location ~ \.php$ block:

fastcgi_read_timeout 300;

Start with conservative pm values and raise them based on RAM and traffic. Each PHP worker uses memory. A rough starting point on a 2 GB Droplet:

pm = dynamic
pm.max_children = 10
pm.start_servers = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 4
pm.max_requests = 500

Enable the built-in status page for monitoring. Add to the pool file:

pm.status_path = /fpm-status

Add a matching Nginx location (restrict access to your IP):

location ~ ^/fpm-status$ {
    access_log off;
    allow 127.0.0.1;
    deny all;
    include fastcgi_params;
    fastcgi_pass unix:/run/php/php8.1-fpm.sock;
}

For WordPress on the same stack, follow How To Install WordPress with LEMP on Ubuntu 22.04. The Nginx and PHP-FPM wiring is the same on 24.04 and 26.04 when you use the correct socket path from the version table.

Ubuntu 24.04 LTS (Noble) and 26.04 LTS (Resolute) use the same Nginx layout as 22.04: server blocks in /etc/nginx/sites-available/, the snippets/fastcgi-php.conf include, and www-data as the Nginx user.

Differences to watch on newer LTS releases:

DigitalOcean LEMP tutorials currently target Ubuntu 22.04. The install and config steps in this guide apply to 24.04 and 26.04 when you substitute package names, service units, and socket paths from the version table. I have not re-tested every command on a fresh 26.04 image in this refresh, so run php -v and ls -l /run/php/ on your Droplet to confirm paths before you go live.

1. Does NGINX use PHP-FPM?

Yes. Nginx has no embedded PHP engine. For .php files, Nginx forwards the request to PHP-FPM through FastCGI. You wire the connection with fastcgi_pass in a location ~ \.php$ block.

2. How do you install NGINX and PHP-FPM on Ubuntu?

Install Nginx, then the FPM package for your LTS release:

Enable both services (example for 22.04):

sudo apt update
sudo systemctl enable --now nginx php8.1-fpm

Add a server block with fastcgi_pass pointing at the socket for your PHP version. The full LEMP walkthrough for 22.04 is in How To Install Linux, Nginx, MySQL, PHP (LEMP stack) on Ubuntu 22.04.

3. What does PHP-FPM do?

PHP-FPM is a process manager for PHP. A master process controls worker processes that execute scripts. Pools define sockets, users, and scaling rules. PHP-FPM is the required PHP handler when you use Nginx.

4. What causes a 502 error with PHP-FPM?

A 502 means Nginx could not get a valid response from PHP-FPM. Common causes include a stopped PHP-FPM service (php8.1-fpm, php8.3-fpm, or php8.5-fpm), a wrong socket path in fastcgi_pass, socket permission errors, or PHP crashes in the worker. Check /var/log/nginx/error.log and journalctl -u php8.1-fpm (swap the unit name for your PHP version).

5. Is PHP-FPM necessary with NGINX?

Yes, if you want Nginx to run PHP. Without PHP-FPM (or another FastCGI PHP handler), Nginx serves only static files. PHP-FPM also separates PHP memory from the web server process, which is why most production Nginx stacks use it instead of older CGI methods.

You installed PHP-FPM, created a custom pool, connected Nginx with fastcgi_pass, and learned how to test the stack and fix 502 errors. Separate pools give you per-site users, sockets, and worker limits.

For multiple PHP versions on one host, see multiple PHP versions on Ubuntu. For HTTPS, follow How To Secure Nginx with Let’s Encrypt on Ubuntu 22.04.

What’s next

Keep building with these PHP tutorials and Nginx tutorials:

• How To Install Linux, Nginx, MySQL, PHP (LEMP stack) on Ubuntu 22.04 (swap PHP package names per the version table on 24.04 or 26.04)
• How To Install WordPress with LEMP on Ubuntu 22.04
• How To Install PHP 8.1 on Ubuntu 22.04
• Nginx Essentials: Installation and Configuration Troubleshooting
• Initial Server Setup with Ubuntu

Deploy from GitHub with DigitalOcean App Platform or run the full stack on a Droplet. Choose an Ubuntu 26.04 LTS image when you create the VM if you want the newest LTS with PHP 8.5 in the default repositories.