TTYL is an initialism used in texting and chatting that stands for "talk to you later". It is a casual and informal way to say goodbye for now, similar to "see you later" or "goodbye". TTYL is often used to indicate that the sender is leaving the conversation but will talk to the recipient again soon. It can be used as a standalone message or in the middle or end of another message, and it can be all-capitalized or lowercase. Here are some examples of how to use TTYL:

• "I have to go; my phones about to die. TTYL."
• "Ill TTYL, the concert is about to start!"
• "TTYL, I have to finish up my homework."

TTYL is one of many abbreviations that sprang into widespread use in the 1980s and 1990s with the rise of instant messaging platforms like AIM, ICQ, and MSN.