Three months ago, I set out to build a document scanner for Android. Not a tutorial project -- a real, production-ready app that could compete on the Play Store.
110 Kotlin files and 21,000 lines of code later, I had something I was proud of. But I also had a realization: most Android devs who need document scanning in their app don't want to build this from scratch.
So I'm selling the complete source code.
What Took 3 Months (And Why)
Building a scanner sounds simple until you actually do it. Here's what ate most of the time:
1. CameraX Frame Stability
Users tap "capture" while their hand is moving. Every. Single. Time. I had to build an RMS-based frame stability analyzer that compares consecutive camera frames and only allows capture when motion drops below a threshold. Without this, 40% of scans were blurry.
2. ML Kit OCR With Invisible Text Layers
Getting OCR text from ML Kit is the easy part. The hard part? Positioning that text at the exact bounding box coordinates inside a PDF so users can select individual words in any PDF reader. Most scanner apps dump all OCR text at the bottom of the page. Mine places it precisely where it belongs.
3. Image Enhancement Pipeline
Six different enhancement modes including Otsu's thresholding for converting color scans to clean black-and-white documents. Plus a real-time ColorMatrix-based enhancement system that runs before the user even taps save.
4. Monetization That Actually Works
RevenueCat integration with 4 paywall variants, A/B tested via Firebase Remote Config. Metered free tier. Weekly/Monthly/Annual plans. Product flavors for free and premium builds with different scan limits. This alone took 2 weeks to get right.
5. Everything Else
- AES-256-GCM document encryption
- eSign with draw, type, and image signatures
- Google Drive backup with OAuth
- QR/Barcode scanner
- DOCX export (no Adobe SDK needed)
- Biometric app lock
- ZIP batch export
- 3-page animated onboarding
- GitHub Actions CI/CD pipeline
- Fastlane deployment config
- Privacy Policy + Terms of Service
- Play Store listing copy
The Tech Stack
Kotlin 2.0, Compose BOM 2024, CameraX 1.4, ML Kit, Room 2.6, Hilt 2.51, RevenueCat 8.3, Firebase, Coil, Lottie, WorkManager. Clean Architecture with MVVM + StateFlow.
Who This Is For
If you're an Android developer who wants to ship a scanner app without 3 months of boilerplate, this template saves you 400+ hours of work.
A freelance Android dev costs $80-150/hr. This template is $149. Do the math.
Get It
I'm selling ScanVault Pro on Gumroad for $149 (normally $249 -- launch pricing).
Use code LAUNCH50 for 50% off -- only 5 codes available.
One-time purchase. Unlimited projects. 30-day money-back guarantee.
Questions? I built every line of this code and I'm happy to walk you through it.
Top comments (0)