Yoast SEO: Install using Composer
What is Composer?
Composer is a dependency manager tool for PHP projects (similar to NPM) and can be run from your terminal.
Installing Composer
To get Composer installed on your system, make sure you follow the official installation steps.
Installing Yoast SEO via Composer
To install Yoast SEO via Composer, run the following command in your plugins directory:
composer require yoast/wordpress-seo
The command above downloads the latest version of the Yoast SEO plugin and installs all necessary dependencies.
Installing a development version of Yoast SEO
If you are looking to help develop Yoast SEO (i.e. patch a bug, for example), we recommend you use git clone git@github.com:Yoast/wordpress-seo.git as we don't support downloading development versions of Yoast SEO through Composer.
Post-installation
Once Composer has completed its installation process, or git is done cloning the repository, please make sure you run yarn, followed by grunt:build in the wordpress-seo directory to ensure all necessary files are properly built.
Updating dependencies
Composer tracks the state of the project in the composer.lock file. Running composer install will always reproduce that state, ensuring consistency across developers' setups.
When dependencies need to be updated the following command will bring said dependencies to the latest versions, as far as is allowed by the version restrictions set in composer.json.
composer update
After that, the updated composer.lock file needs to be committed into version control.
Please note that updating dependencies is somewhat of a delicate process and doing so might result in breakage.
Always properly test before committing an updated version of composer.json and composer.lock.