We do prefer sync over async communication but that its totally optional, you should not feel constrained to work on our work schedule 9 AM-5 PM EEST. We are aware that sync communication is costly, interrupts people’s thought processes and productive execution - that being said, sometimes it is indeed necessary to have a sync interaction, just make sure it is for the right reasons.

When using Slack or similar, try to communicate as much as possible in channels that everyone can access rather than private channels, whenever that can be avoided. We prime visibility and open dialog.