How to build an event registration system from capacity to check-in

Manage event options, attendee details, capacity, payments, confirmations, changes, reminders, and on-site check-in in one reliable flow.

Who this is for

Conference organisers, training teams, communities, venues, and businesses running recurring events with more complexity than a simple form.

What you will get

- A registration model for tickets, sessions, and capacity

- Reliable payment and confirmation states

- An attendee list ready for communication and check-in

Model what can fill up

An event may have ticket types, sessions, meal choices, rooms, time slots, or seats with separate capacity. Decide whether limits apply per order or attendee. Keep reserved, paid, cancelled, and checked-in counts distinct.

Collect attendee data at the right level

An order purchaser and an attendee may be different people. Store contact, accessibility, consent, and session choices against the correct record. Ask only what organisers will use, and restrict sensitive details to relevant staff.

Coordinate capacity and payment safely

Hold capacity briefly during checkout, then confirm registration only after provider-confirmed payment. Expire abandoned holds and make webhook processing idempotent. A payment success page in the browser is not the final source of truth.

Make confirmation useful

Send the attendee a durable registration reference, event details, calendar link, ticket or check-in code, and a safe way to update permitted fields. Operators need the same record and a complete history of changes.

Plan cancellations, transfers, and waitlists

Write policies before launch. Decide who may cancel, transfer, or receive a refund, and when capacity reopens. A waitlist offer should expire so one unanswered invitation does not block the next person.

Design check-in for unreliable conditions

Support fast lookup and scanning, prevent accidental duplicate check-in, and record who performed an override. Prepare a cached or printable fallback for poor connectivity, then reconcile changes when the connection returns.

Frequently asked questions

What records does an event system need?

Start with events, ticket or session options, orders, attendees, payments, capacity holds, communications, and check-in events.

How do you prevent overselling?

Reserve capacity atomically during checkout, expire holds, and confirm only after verified payment while handling repeated webhooks idempotently.

Should tickets belong to the buyer or attendee?

Keep the order buyer and each attendee separate so group purchases, transfers, and personalised communication work correctly.

What should happen if internet fails at check-in?

Use a planned offline or printable fallback and reconcile check-in events later without silently creating duplicates.