TZProof

TZProof is a web app (with lightweight mobile companion) that prevents time-zone mistakes by generating “verified” meeting times for every attendee before an invite is sent. It plugs into Google Calendar and Microsoft 365, detects each participant’s likely time zone from account settings, recent location signals (optional), and email domain heuristics, then asks for a one-tap confirmation when confidence is low. The organizer sees a simple risk score (DST change, travel risk, ambiguous zone, offset-only entries) and can lock the meeting to an IANA time zone instead of a floating offset. For cross-border teams, it also creates a shareable confirmation page that shows the meeting time in each attendee’s locale and requires acknowledgement for high-risk meetings. It’s not glamorous, but it reduces the costly “missed call” problem that keeps happening even in 2026.