At my last startup, this was a constant pain point. We had a bunch of different trials going for different lengths and feature sets, we were constantly experimenting with different pricing models, etc. Managing what features were available for each user in the apps/website got more and more challenging as it went on. A quick Google search didn't yield any tools to make this easier. Some integration with Stripe would be awesome too (to handle when someone's subscription lapses or something). Maybe something like LaunchDarkly would get me halfway there, but I'm looking for other options!