The message text must be in UTF-8 and it allows inserting emojis as individual characters: 🤗💐😂🤩😭 and so on. If you are using systems that, for whatever reason, cannot send emojis, you can use special characters that will be replaced with emojis:

EmojiCode
🤗:sm01:
💐:sm02:
😂:sm03:
🤩:sm04:
😭:sm05:
😤:sm06:
🤝:sm07:
😃:sm08:
😉:sm09:
😍:sm10:
😘:sm11:
😷:sm12:
😕:sm13:
🙏:sm14:
👉:sm15:
👍:sm16:
💐:sm17:
🔥:sm18:
🕒:sm19:
🎁:sm20:
📺:sm21:
:sm22:
🚀:sm23:
💰:sm24:
💜:sm25:
📋:sm26:
🔸:sm27:
🔹:sm28: