Sold out doesn't mean over.
Cancellations auto-promote the next in line.
When a tier fills, the button flips to Join waitlist. When someone refunds or cancels, we email the next attendee on the waitlist with a 24-hour claim link. No manual chasing, no lost fill rate, no organizer scrambling on WhatsApp at 11pm.
The fill loop without an organiser in it.
Sold out at 4pm. Someone cancels at 6.02pm. First waitlist entry emailed at 6.02pm.
Because a 8pm cancellation shouldn't mean an empty seat at 10am.
Product Summit 2026, VIP tier, 40 seats, sold out three weeks before the event. The night before the event, seven refund requests came in — flu season, work travel, one cancellation from a founder whose company got acquired that morning. Our organiser sat at his laptop till 1am forwarding a Google Form to a WhatsApp group of "people who asked to be added if a seat opens." Two of the seven seats got filled. Five went empty.
Every event we run has this pattern. Cancellations cluster in the last 72 hours. Nobody in ops has capacity to chase a waitlist manually at midnight. The organiser gives up. The room is 12% less full than it should be. Attendees who wanted in feel forgotten. Sponsors count empty chairs.
So we made the loop close by itself. Sold-out button flips to Join Waitlist. Cancellation hits our OrderService. OrderService hands off to WaitlistService. WaitlistService emails position #1 with a signed claim link. Claim link expires in 24 hours; if they don't claim, we auto-invite position #2. No human in the loop until the attendee actually walks through checkout.
On the same event, we re-ran the numbers. Of the 7 cancellations, 6 got filled by the waitlist within 4 hours. One expired without a claim — moved to position #2 who took it. Zero seats empty. Organiser slept.