At the beginning of the competition (which has traditionally been a Friday at 9PM Eastern Time Zone). The submission page will remain open for 48 hours for the strict competition and 72 hours for jam after which the submission pages close. There is a 1 hour grace period called “Submission Hour” in case you spend the entire time working on the application. After that time period (Sunday/Monday 10PM EDT for the compo/jam) submissions will no longer be taken.