Lead architect and developer for VaxiCode—Quebec’s COVID-19 vaccine passport app. 8 million downloads. Also shipped the same system in Saskatchewan and Newfoundland.
When the government announces a vaccine passport mandate, there’s no phased rollout. We went from “this needs to exist” to “8 million people are trying to download it” in a few weeks. The app had to work offline (you don’t always have cell signal at a restaurant entrance, and fully offline is the ultimate privacy assurance), handle multiple proof formats, and be usable by everyone from tech people to grandparents who just learned what apps are.
Built on React Native for cross-platform. The verification uses SMART Health Card standards—the same spec Apple and Google adopted later. The interesting technical challenge was making verification work entirely offline. You can’t call a server every time someone scans a QR code at a bar entrance. All the cryptographic verification happens on-device, with key updates syncing when connectivity is available.
I’ve shipped a lot of software, but nothing compares to the pressure of public health infrastructure during a pandemic. When the app doesn’t work, it’s on the news. When verification is slow, people are standing outside in the cold.
It worked. Could’ve been smoother in places, but it did what it needed to do.