Undo founder here. We've been at this for getting on 20 years now. Originally it cost $295 for a perpetual license. Eventually we understood that the majority of developers (actually employers of developers) will pay $0. But some are happy to pay for tooling, as long as they're confident they'll get a many multiples return-on-investment. Hence our pricing. Happily, enough do that we can run a modest but profitable business (40+ people). Customer churn is practically zero.

Why do people pay for Undo when they can get rr -- which is also really good -- for free? Those whose code or environment is big enough and complex enough that rr doesn't work for them, and they understand how powerful time travel debugging is. If rr works for you, you should use it. This includes most independent developers.

If rr can work for you and you're still not using any kind of time travel debugging, you have effective tied one hand behind your own back! If you're independent (incl student or academic) and rr doesn't work for you, get in touch -- we give free licenses for academic and certain other use cases.

There is a wider thing here about software companies paying for dev tooling. So many companies over the years who made really cool things who couldn't make their business work.

> If […] you're still not using any kind of time travel debugging, you have effective tied one hand behind your own back!

Completely agree about that! I’ve used rr to debug things that I never could have without it. People are resistant to change though.