Building on strange surfaces
Apple Wallet, Keypass, AirCard, and why the strangest surface is often the most fun one to build on.
Sep 29, 2026The most fun place to build is often somewhere nobody thinks of as a platform. The surface doesn't have to be conventional. It just has to already do something well, and then you get to play with that.
A source of truth
People think of Apple Wallet as a place for things that are already real: a boarding pass, a credit card, a ticket. If something is in Wallet, it feels official. The pass doesn't prove anything by itself, but the interface lends it trust, and that changes how people react to what they see.
That gap is a fun one to play in. Keypass, an iMessage agent I built, turns a public Luma event link into an Apple Wallet pass. It has 7,000 users and 700k impressions. What stuck with me wasn't the growth so much as how little I had to invent: a text message, a pass, and everyone's existing belief that a pass in Wallet means something.
Reskinning it
AirCard, an open-source project by mak5er, goes at the same surface from the other side. It reskins the cards already sitting in your Wallet with your own artwork, and it works without a jailbreak. Nobody designed Wallet to be a canvas, but once someone finds the seam, it becomes one.
That's the part I like. You don't fight the surface, you use what it already does, and you find out how much room is in there.
The absurd part
There's a third thing I like to call the absurdity part. I'm working on a way to send notifications to everyone who holds your Wallet pass, and I want to use it to build a platform where people write and deploy notifications for secret messages.
Passes can be shared, but only by people who already have one. So a secret can only travel through people who were already let in. Wallet passes were made for boarding gates and coffee cards, and repurposing their sharing and notification features into a secret-message network is a ridiculous thing to build.
That's the appeal. Pick a surface, ask what it already does well, and misuse it on purpose. The absurdity isn't a side effect. It's how I find the ideas worth building.
Zhiyuan Guo
zygl.dev