Timespree

Timespree is a free group-scheduling poll, like When2meet but mobile-first. Share one link, and everyone paints the hours they are free on a grid. The overlap shows up as a heatmap, so the organizer books the time that works for the most people in seconds, with no email thread. Each person sees the grid in their own time zone automatically, and they can privately overlay their Google, Outlook, or Apple calendar busy times while responding. There is no participant limit and no account needed to respond. Free and ad-supported.