100x.bot is completely powered by daptin, canaster.in (work in progress, i am redoing the frontend in webgl) is also running on daptin. there are various internal company services which are running on daptin which i cannot name here.

almost any project which matures to requiring a user authn/authz (and there are always assets owned by users) i default to using daptin

I have hardened it a lot over the last 10 years, especially in terms of transaction/concurrency/security. happy to help you setting it up in your project. you can dm me ( x.com/phparth ) or leave an issue on the github repo