There are several bot API libraries out there, so why should you pick tourmaline? Here are a few reasons I can think of:
Tourmaline, having been built with Crystal, is fast. If you're not overly familiar with Crystal you may not understand why, so here's the short of it:
Crystal is a high performance, statically typed language with speed close to that of C. With that you may think "well then, it must have a terrible syntax", and I wouldn't blame you. Most fast languages are terrible to write in. But Crystal was inspired by Ruby, and has an almost identical syntax.
Speed has never looked so good.
Tourmaline's whole goal is to make it so you can write the least amount of code as possible, while still getting a great result. As such it is full of convenience methods and little things that many bot libraries tend to skip over, or think of as bloat. We can get away with this in Crystal because Crystal's compiler doesn't include any unused code in the final binary.
It's both easy and fast to get help with Tourmaline. You can file a bug report in the github repo if you want to request a feature or something is broken, but you can also reach out on Telegram itself at @protoncr. Someone will likely respond within minutes.