Diary with Lock - Flutterflow App
János Kiss
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Posted Jul 3, 2025
Developed a secure, cross-platform diary app with privacy features.
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Timeline
Sep 3, 2024 - Sep 24, 2024
Your thoughts, protected — a beautifully minimal and secure diary app with built-in privacy lock.
Project Overview
Diary with Lock is a sleek and secure personal journal app designed for individuals who value both simplicity and privacy. Built for web, iOS, and Android platforms, the app enables users to effortlessly capture daily reflections, emotional entries, or creative thoughts—while ensuring these stay private through timed auto-lock and biometric protection. Its clean interface makes journaling a joy, whether you’re on desktop or mobile.
Key Features
🔒 Auto-lock after 30 minutes of inactivity or app backgrounding for enhanced privacy
✍️ Minimalist and intuitive UI/UX focused on distraction-free journaling
📄 Export entries as PDF with rich formatting for long-term backup or sharing
🧠 Streak counter to motivate daily writing habits
💡 Formatted HTML text editor widget for beautiful entries
💎 Free and premium tier system, with seamless payment and unlock logic
Tech Stack & Integrations
FlutterFlow (cross-platform UI & logic development)
Firebase (auth, Firestore, functions)
Stripe (for web payments)
RevenueCat (for iOS & Android subscription management)
Challenges & Solutions
Lifecycle Management & Permissions: Implemented cross-platform logic to auto-lock the app securely after inactivity or when leaving the screen—solved with platform-aware lifecycle tracking.
Cross-Platform PDF Export: Ensured high-fidelity PDF export with styled text across web, Android, and iOS, resolving platform inconsistencies.
Subscription Sync: Unified RevenueCat and Stripe data to reflect accurate subscription status across all platforms.
UI Simplicity: Maintained an ultra-clean interface while still supporting rich formatting tools and export features, using custom FlutterFlow widgets.
Development Time
🚀 2 weeks from design concept to fully functional web and mobile builds.
Impact or Outcome
✅ Web app is live and fully functional: Try it here
📱 iOS & Android versions are ready for store deployment—awaiting client go-live
My Role & Value
As the sole FlutterFlow expert, I led the app from scratch to production, covering UI/UX design, backend setup, integration implementation, and deployment support. My focus was on speed, clean design, and cross-platform harmony, ensuring the app feels native and polished on every device. I also optimized the payment system across web and mobile using Stripe and RevenueCat, saving the client time and future maintenance headaches.