[dahart]

> Feature flags are a nice idea, but nobody outside of Facebook seems to be embracing them. The tooling just isn't there.

This might be just a terminology problem. Any company that does A/B testing is using feature flags, so pretty much most of the web is using them. I'd bet more or less all programmers have them in their repos too, maybe you just call them something else, or didn't think they could be called feature flags. If you have a config file, chances are high that you have feature flags already.

For tooling, I get the feeling you're thinking of feature flags as something other than your config files and code constants. But that's it: feature flags are really simple. Add a boolean const defaulted to false in your config somewhere, and wrap the code in an if statement. When you need to A/B test or release incrementally, that's when you need extra non-trivial code around features, and that's often not something someone else can provide. Turning the feature on and off requires specific knowledge of your project's stack and UI.