cardpulse
CardPulse is an iPhone app for card collectors who think like investors: one watchlist, live market prices, alerts when a card crosses your target, and a verdict on whether grading a raw card is worth the bet. Solo project, live on the App Store.
I collect Pokémon cards, and the routine annoyed me: for every card I was watching, I had to search it up again, every single time, across price sites and sold listings. Nothing would just tell me when a card I cared about dropped below or rose above a price. The app I wanted was one watchlist for all of it, with notifications doing the watching for me. It didn't exist, so I built it.
The loop is simple: add a card, and CardPulse tracks its market price, shows your return since the day you added it, and fires an alert when it crosses your target. The screen I'm proudest of is card details. It carries a lot: raw versus PSA 10 pricing, price history, demand pressure, supply saturation, and a grading verdict computing whether sending the card to PSA is worth it across grade outcomes. The design job was making that density scannable instead of overwhelming, and it took the most iterations of anything in the app.
Because the app is about money, the data rules are strict and written down. Returns are measured from the moment you added the card, observed by the app, never backdated to a purchase price it doesn't know. When there's no previous close, today's return prints a dash, not a zero. Market metrics come from a named data partner and the app says so. Collectors can smell invented numbers; the product's whole value is that its numbers can be trusted.
Card price data is the product's oxygen, and good data is expensive for a solo app. Instead of scraping or paying rates that would sink it, I offered the data providers a revenue share. It costs margin on every subscription, and it's the right long-run call: the incentives line up, the data keeps flowing, and the partnership survives the app growing.
- 2,000+
- users since launch
- 19
- releases shipped since May 2026
- $4.99
- a month, free tier included
CardPulse shipped to the App Store in May 2026 and has been shipping ever since, on a freemium model with Premium at $4.99 a month. The brand went with it: the prism mark reads as a card held at angle, a graded gem, and a peak on a price chart all at once, and the product voice is direct, quantitative, with dry humor when earned.
This is the project where every hat was mine: research, brand, product, code, App Store releases, even the data partnerships. Owning the whole loop taught me more about why products succeed than any single role ever has. And building for a community I belong to kept the bar honest, because I'm the user who gets annoyed first.