Note: This is written for those using Python 3 and discord.py, so if you're using something else please reference the relevant documentation for your language or library if you choose to use this as a general reference.
On Discord, there are two different emoji types:
Each needs to be handled differently, as while unicode emoji are just simple unicode characters, Discord custom emoji are special objects available only in Discord, belonging to a specific Discord guild and having their own snowflake ID.