The two kinds of cURL

Install or update the cURL command

# AlmaLinux, Rocky Linux, CloudLinux
dnf install -y curl

# Development headers, only if you compile software against libcurl
dnf install -y libcurl-devel

curl --version

cURL is installed on almost every server already. Keep it updated with your normal system updates, because cURL security fixes arrive through the operating system packages. Do not compile cURL from source on a cPanel server; it can conflict with the system libraries.

Install the PHP cURL extension in WHM

1. Log in to WHM as root and open Software > EasyApache 4.
2. Click Customize next to the currently installed packages.
3. Open PHP Extensions and search for curl.
4. Turn on ea-phpXX-php-curl for every PHP version your sites use, for example ea-php83-php-curl.
5. Click Review, then Provision.

You can install the same packages over SSH:

dnf install -y ea-php83-php-curl ea-php84-php-curl
/scripts/restartsrv_apache_php_fpm

On CloudLinux servers that use PHP Selector, account owners can also turn the extension on themselves in Select PHP Version. See our PHP Selector guide.

Check that PHP cURL works

# For one PHP version
/opt/cpanel/ea-php83/root/usr/bin/php -m | grep -i curl

# Show the libcurl version PHP uses
/opt/cpanel/ea-php83/root/usr/bin/php -r "print_r(curl_version()['version']);"

To check from a website, create a temporary info.php file with <?php phpinfo();, open it in the browser, search for “curl”, then delete the file.

Useful cURL commands for server work

curl -I https://example.com/              # headers only: status code, redirects, cache
curl -L -o file.zip https://example.com/file.zip   # follow redirects and save to a file
curl -v https://example.com/              # full connection details, useful for SSL problems
curl --resolve example.com:443:203.0.113.10 https://example.com/   # test a new server before DNS
curl -X POST -d "name=test" https://example.com/form   # send form data

A simple PHP cURL request

<?php
$ch = curl_init('https://api.example.com/status');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 10);
$response = curl_exec($ch);
if ($response === false) {
    echo 'cURL error: ' . curl_error($ch);
}
curl_close($ch);

Always set a timeout, so a slow remote service cannot hold your PHP processes.

Use cURL safely in scripts

• Never turn off certificate checks with -k or CURLOPT_SSL_VERIFYPEER = false in production. Fix the certificate problem instead.
• Keep API keys out of the command line, where other users can see them in the process list. Read them from a protected file instead.
• Download install scripts to a file and read them before you run them, rather than piping them straight into bash.

Troubleshooting