It’s a really interesting question and I could talk for hours about this!

There is one very significant part of the c.t stack which I’ve released as open source and that’s tilemaker – the code that makes the mobile maps. I’ve written a lot of open-source code over the years, mostly in connection with OpenStreetMap, and I do keep half an eye out for opportunities to release other tools like this; maybe there’ll be some chances in the future.

In business terms the issue is basically that c.t largely differentiates itself by the quality of its routes. I can’t compete on marketing, or on sheer engineering force; but my hope is that enough people like the routes c.t generates that they choose to support the site, and to tell others about it.

c.t’s competition is mostly either very big (Komoot has 200ish employees) or also pretty small (lots of other single-person operations). Open-sourcing the routing would be an open invitation to be crushed by the big guys. Open-sourcing the apps is slightly less suicidal, but effectively gives a leg up to the other single-person operations. I also don’t really want to get into having to openly maintain the interface between app and server in a way that doesn’t let me just change stuff. ;)

All of which is to say that open-sourcing the core of c.t is unlikely. But I will continue to look at whether there are more components like tilemaker that I could potentially release.

Very fair points! Thanks for the comprehensive answer.

Indeed the routes are primarily what's driven me to this app and makes me love it.

Maybe offering routing-as-a-service to other apps could be interesting too? But I digress.

CT appeals to me for two real reasons:

• It's faster and works much better (for me) than what I used before. The actual functionality is the best I've seen, though admitedly I ruled out many popular competitors because they fail the next point.
• CT is privacy-friendly. I can just use it for making routes, and don't have to worry about nefarious tracking, social features, or any other such nonsense. I can make everything private if I want to, and the privacy policy is refreshingly reasonable.