In short, yes, you can use composer on the Eco Web Hosting platform although you may need tweak the commands to use if you need a specific version of PHP when running and/or you receive a version warning when attempting to run.
For example, after downloading composer and running the standard command to install...
composer install
...this will use the default version of PHP which may not be what you need here so the command will need updating to specify the binary for the version of PHP you wish to use...
/usr/bin/php73 -f /usr/bin/composer install
...will run the installation process using PHP7.3. Any further commands will also need updating in this manner to specify the version to use each time.
A full list of versions will be presented the first time you login to the package using SSH if needed.
