I maintain Blazor Blueprint, an open-source Blazor component library. I want to talk about something that shows up as soon as a schedule crosses a daylight-saving change, or has to work in more than one time zone: time.

My day job is running a business that builds HRMS software. It's a regional application, and our customers have employees spread across different time zones. Shifts, leave, rosters, public holidays: scheduling sits right in the middle of it, so an accurate calendar matters a lot to me.

When clocks spring forward, a night shift is an hour shorter. When they fall back, it is an hour longer. Get the local times wrong and you pay the wrong hours, or a start time lands in an hour that never happens.

If you have ever stored a weekly 9:00 meeting as UTC and then watched it jump an hour when daylight saving changed, you already know the problem.

Wall time is what people mean. Nine in the morning in New York. Instant time is what computers mean.…