Can I create a commercial app using telegram API?

First question: Can I create a different type of commercial app using telegram API?

For example, can I create a dating app based on Telegram API using groups as chat rooms for my users?

Second question: Do I have to publish my code to GitHub?

I see bunch of unofficial Telegram apps on Play Store and I can't find their code on Github. But it is mentioned that 'Unofficial Telegram apps that is based on Telegram API must publish their code to Github to meet the license requirements' in T开发者_运维技巧elegram license.