Implementations for downloadable cartridges for a multi-tenant Platform-as-a-Service (PaaS) system are disclosed. A method of the disclosure includes receiving, by a processing device of a multi-tenant Platform-as-a-Service (PaaS) system, a location of a cartridge manifest corresponding to a cartridge that is maintained outside of the multi-tenant PaaS system, downloading the cartridge manifest from the received location, parsing the downloaded cartridge manifest to determine a source location of files of the cartridge, the source location separate from the multi-tenant PaaS system, and causing the files of the cartridge to be obtained from the determined source location for use by at least one node of the multi-tenant PaaS system that is hosting an application requesting the cartridge.