Checklist - open source. This I would do my self too, but only because I am a technical person - version control. Agree, but in my case only API will be available for you to version (versions are of course in backend too) - testing. Agree and this is important. But what kind of testing? Would end-to-end tests be enough i.e. separated env with data set and Postman? - self-hosting. Private SaaS anyone? - functionality: thanks for reminding me of the importance of loops, variables, and conditions. These can be implemented. - authentication and authorization. Definitely required for mature software!