tkt
The English phrase 'wdym' corresponds to the French tkt.
In French text messaging, tkt is used as an abbreviation to tell someone not to worry.
Example conversation
Lucas is texting Léa because he is running late for their meeting.
- LucasDésolé, je vais avoir dix minutes de retard !Sorry, I'm going to be ten minutes late!
- LéaTkt, je t'attends au café.Don't worry, I'm waiting for you at the cafe.
- LucasMerci beaucoup, à tout de suite.Thanks a lot, see you in a bit.
- LéaÀ tout de suite !See you soon!