Using MQTT to make a MMO

Does anyone know if MQTT is ideal for a MMO multiplayer game, like how well it will handle many players.
Also does anyone know where i can learn everything about the MQTT extension, like every expression and everything that i have to know. The wiki dosen’t teach me a alot how to use it, so i can’t really figure out how to learn the extension.
On top of that i can’t seem to find any MQTT broker servers i can hire. If you know any websites that does that lmk.