The hard parts of building event software.
Engineering notes on ticketing, event time, Wallet, check-in and the infrastructure behind reliable event products.
Check-in · Short note
Scanner A + Scanner B → one ticket transition
Why check-in needs an atomic state transition
Two scanners can read the same ticket. Only one should record its first admission.
Read noteEvent time · Short note
19:00 Sydney + Australia/Sydney → 08:00 UTC
Why event time isn’t just a UTC timestamp
Collect the organiser’s local time and timezone, resolve the instant, and keep that context when you send it to Eventlayer.
Read noteApple Wallet · Short note
Ticket changes → push notification → Wallet fetches pass
What happens after a Wallet pass is installed
An installed pass is still connected to its ticket. Registration, push notifications and a fresh download keep it up to date.
Read noteWebhooks · Short note
Verify → durable inbox → acknowledge → process
Building webhook consumers that survive retries
Verify the request, record the event, then acknowledge. Keep repeated deliveries from repeating the work.
Read note