OP here. It's true that Heroku were required to pre-install a lot of dependencies, because they don't offer a way for developers to specify additional dependenc

OP here. It's true that Heroku were required to pre-install a lot of dependencies, because they don't offer a way for developers to specify additional dependencies to be installed on their servers. On the contrary, with pkgr.io, additional build and runtime dependencies can/must be added by the package maintainer if anything other than the base stuff is needed. See https://pkgr.io/doc#dependencies https://pkgr.io/doc#dependencies and, as an example, the .pkgr.yml file for a fairly complex project such as Gitlab: https://github.com/pkgr/gitlabhq/blob/pkgr/.pkgr.yml https://github.com/pkgr/gitlabhq/blob/pkgr/.pkgr.yml.