Shameless plug (it's my project!), but there's also Flagsmith - https://github.com/Flagsmith/flagsmith
For completeness, the other OS projects I know of are:
- https://github.com/markphelps/flipt
For completeness, the other OS projects I know of are:
- https://github.com/markphelps/flipt
Not totally sure Flipper is in the same category - that's more a Ruby-specific library, no? I know they have a cloud offering, but that isn't open source.
One more I found: https://github.com/checkr/flagr