Is PHPDevShell multi-project?

Yes, a single installation of PHPDevShell can handle several projects. It's possible because:
- everything is a plugin, so your project can be packaged as a plugin (several projects on the same server can share other plugins like utilities)
- a project has its own database, so, based on the site name, PHPDevShell will use a different database and therefore a completely separated environment

Please take a look at the document about configuration to learn how to host several sites with a single installation.