trying to have a go at magento 2, I have the latest PHP.

Error message:

Vendor autoload is not found. Please run 'composer install' under application root directory

Where do you install composer, on the root of your server/in root magento directory or in the magento setup directory?

3 Answers 3


You could actually put it anywhere, what really matters is where you run it from. If you download composer and put it somewhere in your cli PATH then all you need to do is cd to your magento directory and then run "composer update", however you could also put it in the magento directory and run it from there.

You may already know but just to be clear. The CLI tool doesn't actually have anything to do with running the Magento application. The main thing Composer takes care of is downloading and installing the dependencies of the project, it will also create an autoload file so that those dependencies can easily be loaded from the application.

  • Hi there I'm getting error The requested PHP extension ext-xsl * is missing from your system" Commented Jul 16, 2015 at 11:02
  • 1
    This is telling you that your php install doesn't have the required xsl extension, you need to install that on your server. You can use --ignore-platform-reqs to bypass the php requirements but Magento may not work without it. e.g composer install --ignore-platform-reqs Commented Jul 16, 2015 at 11:09
  • Be aware that PHP-cli may use a different configuration (.ini) than for the web. I ran into that with my UniServer install; couldn't figure out why composer was saying the extensions weren't active. That was why.
    – Ryan Hoerr
    Commented Jul 16, 2015 at 11:59

If you are installing on windows try to open command prompt and Rome to your magento directory for wamp server e.g. "c:/wamp/www/magento2" then write command "composer install" after this restart your wamp/xampp server and go to http://localhost/magento2/setup and you are all set for installing magento 2

once you install composer with correct php path you just need to install composer in your magento folder's root directory.


Composer works with any PHP that can support it, so it does have it's dependencies like intl, xsl that usually come with XAMPP or MAMP etc, if not you can install them through pecl, edit php.ini in case they're disabled, uncomment them Installing composer itself it's easy


While you are in the magento root folder run from there the phar composer executable file pathtocomposer/composer.phar install, don't forget to do composer update if you never done it

That will install your library dependencies on your magento/vendor folder

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