German phrase
Bitte sag mir bis ~.
Meaning
Please let me know by ___
When to use it
It sets a reply deadline. It is casual and suits friends or coworkers.
Example dialogue
Bitte sag mir bis morgen Abend, ob du dabei bist.
Please let me know by tomorrow evening whether you are coming.
Ich mache das, ich sage es dir morgen Abend.
I will. I will tell you tomorrow evening.