Application (user level) settings management?

We have a large system with multiple layers of application settings (user, user group, integration partner etc) and over the years it has grown in complexity – there are multiple DB tables and services that teams have created to manage their own config (or to let users do it themselves), and its becoming unmanageable. We're planning the build of another ([7th?](https://imgs.xkcd.com/comics/standards.png)) system, a service for storing all settings as well as a user interface that is generated from the settings (new setting added, new form field appears in UI).

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Is there some open source or commercial tool for this, so we don't have to build it? I tried searching but all I'm finding is application configuration management (ansible etc and a million blog posts about how to use them). Every application with medium complexity is going to need something like this, so I would imaging somebody would have jumped into this market.

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Thanks!

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EDIT: To be clear, I mean settings that drive business logic in the application layer, not DB connection strings or anything like that. Also, it needs to serve a variety of tech stacks so needs to be out of process, accessible in the backend via http api or protobuf or something like that.