Flipspark

Flipspark: Studio Prompt Cards is a creative card game for music producers, now on the App Store. It's the iPhone version of Flipspark Elements, a physical deck built to beat the blank project. Shuffle four suits (Element, Instrument, Pattern, Effects) into a track brief, reroll any card until it clicks, or draw one suit when you only need one idea. Flip a card for a worked example of how to actually pull it off. Add your own prompts, and get a fresh spark every day from the home screen widget. Offline, no account, nothing collected.

How I built it

SwiftUI, built with Claude Code. I steered by feel and let Claude do the plumbing. Some real prompts:

• "add 50% more education on the back of the cards. they just need to fit on the card"
• "here are the Figma v1.2 cards. diff them against the app, number the rows and I'll tell you which to keep"
• "is the UI responsive to other phone dimensions? give me a screenshot first"
• "thinking about release, what have we forgotten? why might it be rejected?"
• "i want the cards to move when you tilt the phone"

Challenges

• The AI repeated itself. Expanding 96 card backs, 69 of the new examples restated the card's own opening line. I only caught it reading one on screen. Fix: a script that flags any shared five word run, then a rewrite down to zero.
• Fitting every phone. Cards scaled to screen width looked great on a Pro Max and ran off the bottom of an iPhone SE. Clamping to height too, then screenshotting three sizes, sorted it.
• Trust the binary, not the build. The studio got renamed mid release. Searching the final archive found the old name still baked in, and later a "Drum" vs "Drums" typo. Both would have shipped on a green build.
• Honest numbers. Apple rejects claims a reviewer can't see. The combo count isn't 16^4, because some cards change or skip the others, so I had it count the real draw: 49,936. "Nearly 50,000" it is.
• Real device only. Tilt parallax needs a gyro the simulator doesn't have, and the launch screen flashed white only on light mode phones. A burst of screenshots proved it.
• App Store traps. The preview video was rejected for "corrupted audio" because it had no audio track at all. Adding a silent one fixed it.