By / Until
Until tells us how long a situation continues. If something happens until a particular time, you stop doing it at that time.
They lived in a small house until September 2003.
(They stopped living there in September.)
Use by for one specific event that will happen before a certain time in the future. Use until for a continuous event that will continue and then stop at a certain time in the future.
Please send me the information by Monday.
He’s staying in London until the 30th.