Install Mcrypt on macOS

Install-Mcrypt.md

Setup php-mcrypt on macOS (and versions of Mac OS X)

These steps should have been mentioned in the prerequisites of the Laravel Installation Guide, since I'm surely not the only person trying to get Laravel running on macOS.

Install

Install Mcrypt using Homebrew and PECL (comes with PHP)

# PHP 7.3
$ brew install mcrypt
$ pecl install mcrypt-1.0.3

Find your php.ini:

$ php -i | grep "Loaded Configuration File"
Loaded Configuration File => /usr/local/etc/php/7.3/php.ini

Add this line to your php.ini:

extension=/usr/local/Cellar/php/7.3.x/pecl/20180731/mcrypt.so

Historic Answer

Install Mcrypt using Homebrew

# PHP 7
$ brew install php70-mcrypt

# PHP 5
$ brew install php56-mcrypt --without-homebrew-php

Add this line to /private/etc/php.ini:

# PHP 7
extension="/usr/local/Cellar/php70-mcrypt/7.0.x/mcrypt.so"

# PHP 5
extension="/usr/local/Cellar/php56-mcrypt/5.6.x/mcrypt.so"

You are ready to go!

Upgrade

Upgrade Mcrypt using Homebrew

$ brew reinstall -fs php71-mcrypt

Support for PHP 7.x runs out in just a few days, you can't be serious about still using 5.x