Signature Maker
Document signing app shipped in 2 days, growing organically to €122 MRR, Co-founder
Context
Signature Maker is an app we shipped in 2 days at 14x, an app studio. I built the iOS app (Swift, on-device ML), my co-founder built the Android app (Kotlin).
We didn't set out to innovate. We noticed dozens of apps already solving this exact problem and wondered: are they all making money? Instead of researching further, we just built one.
The problem
Signing a PDF on your phone should take 10 seconds. Instead, most people still print, sign, scan, and email. The apps that solve this are either bloated PDF suites with 50 features you don't need, or they force you to draw a signature with your finger (which never looks like your real handwriting).
The problem was already well-defined and well-proven by competitors. We just needed to execute it cleanly.
The solution
A single-purpose app with a dead-simple workflow:
- Write your signature on paper with a pen
- Point your phone camera at it
- On-device ML removes the background instantly
- Import any PDF, drag your signature where you need it, export
We added a few extras that made it competitive: a document scanner with edge detection and perspective correction, AI-powered contract review (Gemini flags red flags and complex clauses before you sign), OCR full-text search across all your documents, and Face ID protection.
Everything stays on-device. No accounts, no cloud storage. Privacy was a deliberate product decision, not an afterthought.
The hardest technical challenge was PDF manipulation. Interacting with PDFs programmatically, writing on them properly, handling different page sizes and orientations, getting the signature placement to feel natural with drag and resize... it's surprisingly painful on both platforms.
We also designed a full logo system with primary, on-brand, and dark variants, then ran A/B tests on the App Store to measure which icon converted impressions to downloads best.
The app ships in 43 languages, with localized screenshots for every locale.
Outcomes
The app grew to €122 MRR purely through organic App Store discovery (ASO). No marketing budget, no content strategy, just a well-optimized listing in 43 languages.
We experimented with Apple Search Ads using our internal tool ASA Engine, but it didn't move the needle. The document signing category is brutally competitive on paid keywords. Incumbents bid so aggressively that our budget barely got spent, and the few impressions we did get converted poorly against established brands with thousands of reviews.
The organic channel works because the App Store rewards apps that solve a clear problem well. Good retention signals, solid ratings, and broad localization compound over time.
Retrospective
Honestly, I wouldn't change much. The 2-day build constraint forced us to be ruthless about scope. No feature creep, no second-guessing, just ship the core loop and see if it sticks.
If anything, the only regret is not building it years earlier. The market was already there. The demand was already there. We just needed to show up with a clean execution.
Learnings
Building on proven problems is stupidly easier. You skip the entire "does anyone want this?" phase. The competitors already validated the market for you. Your job is just to execute well.
The App Store is a distribution advantage. If your app solves a real problem and you do proper ASO, the store drives organic downloads for free. Compare that to a webapp where you need to build your own traffic from scratch through SEO, content, or paid ads.
Apple Ads in competitive categories is a trap. The economics don't work for small players. Incumbents bid keywords up to the point where your budget doesn't even get spent. You're not competing on quality, you're competing on who can burn more cash per install.