Product Engineer building privacy-first tools that I actually want to use.
✏️ LeedPDF – PDF annotation without compromise
Turn any PDF into an infinite drawing canvas
- The Problem: PDF annotation tools force you to upload sensitive documents to someone else's servers.
- The Solution: Browser-based annotation with pen-like precision. Zero uploads, total privacy.
- Impact: 3,000+ monthly active users across 175+ countries, 1,500+ desktop app downloads, 300+ GitHub stars.
- Tech: SvelteKit, Tauri (Rust), Canvas API, client-side processing, privacy-by-design
🔗 Try it: leed.my
📧 DoublOne – Email that feels like 2025
Privacy-first email client with chat-style UX
- The Problem: Email UX hasn't evolved since the 90s. Users spend 2.5 hours daily drowning in cluttered inboxes.
- The Solution: Transforms messy email threads into clean, chat-like conversations with sub-50ms performance and zero-knowledge encryption.
- Impact: 40% faster email triage vs traditional clients, growing user base across multiple countries.
- Tech: Flutter, Supabase, PostgreSQL, IMAP/OAuth 2.0, end-to-end encryption
📊 Cristalyse – Flutter data visualization
Grammar of graphics for Flutter
- The Gap: Flutter lacked a comprehensive, performant data visualization library.
- The Solution: 60fps GPU-accelerated rendering with intuitive grammar of graphics API.
- Adoption: 1,000+ monthly downloads with growing community adoption.
- Tech: Flutter, CustomPainter, GPU optimization, mathematical transformations
🌸 PinkRain – On-device ML for health predictions
Privacy-first health journaling with AI
- The Problem: Health apps send sensitive data to remote servers. Users want predictions, not privacy violations.
- The Solution: On-device TensorFlow Lite inference, synthetic data training, HIPAA-compliant by design.
- Impact: 99% micro-F1 accuracy, <5ms inference time. Users stick around because predictions actually help.
- Tech: Flutter, TensorFlow Lite, Bi-LSTM networks, synthetic data generation
🔖 Golden Day – Visual bookmarking without the chaos
Capture anything with a single keystroke
- The Problem: Bookmarks pile up in folders you'll never revisit. Organizing feels like work.
- The Solution: Visual bookmarking with rich metadata extraction, offline-first storage, keyboard-driven workflows.
- Impact: Offline-first, privacy-focused architecture with local-first storage and visual masonry layout.
- Tech: SvelteKit, Chrome Extension API, client-side processing, metadata extraction
🎬 Glucose – Video player that gets out of your way
Ultra-lightweight with on-device AI subtitle generation
- The Problem: Video players are bloated with features you don't need. Subtitles require uploading to servers.
- The Solution: Zero UI experience with keyboard-first controls, on-device AI subtitle generation.
- Impact: Ultra-lightweight desktop app with native performance and cinematic viewing modes.
- Tech: Rust, Tauri, Svelte, on-device AI processing
🧠 CaraML – Multi-LLM interface done right
AI assistant with shared memory across models
- The Problem: Using AI effectively means switching between models for different tasks, losing context each time.
- The Solution: Unified interface with context preservation, smart model routing, seamless switching.
- Impact: 350% faster AI workflows, 94% context retention across model switches.
- Tech: React, LLM APIs, context management algorithms, real-time state sync
🚦 Tuesdae Rush – Traffic simulation game
Control the chaos, prevent the crashes
👆 Click to play the live game 👆
- The Concept: You control traffic lights in increasingly complex intersections. Toggle signals, manage flow, prevent accidents.
- The Challenge: Real-time traffic simulation with collision detection, optimized for smooth 60fps gameplay.
- Tech: Flutter, custom physics engine, state management, game logic optimization
👆 Navigate through my projects in an immersive 3D environment 👆
Built with Three.js, React Three Fiber, and creative engineering
Dart/Flutter • TypeScript • Python • Rust • JavaScript
I've been writing Dart for 5+ years and have shipped production apps with millions of interactions. Python and TypeScript are my go-to for rapid prototyping and backend work. Rust is newer but I've shipped two real products with Tauri.
Frontend: Flutter (mobile), SvelteKit (web), React, Astro, Chrome Extensions
Backend: Node.js, Python (Flask/FastAPI), Supabase, PostgreSQL
Desktop: Tauri (Rust), cross-platform native apps
Systems: Canvas API, WebGL, custom rendering engines
This is what sets my work apart. I don't just build features, I build products people can trust:
- Zero-knowledge encryption and end-to-end security
- On-device ML inference with TensorFlow Lite (no data ever leaves the device)
- Sub-50ms response times through aggressive optimization
- Privacy-first architecture from day one, not bolted on later
- Offline-first design so your data stays yours
Machine Learning: TensorFlow, TensorFlow Lite, on-device inference, synthetic data generation
Data Analytics: Statistical analysis, predictive modeling, A/B testing, user behavior analysis
Business Intelligence: Market analysis (15%+ product launch success improvement), data-driven decisions
My CS degree specialized in Data Analytics, and I apply it to actual product decisions, not just dashboards.
- Building products that respect user privacy while delivering ML-powered features
- Performance optimization (60fps on mobile, <50ms server response)
- Cross-platform development (one codebase, native feel everywhere)
- Shipping fast without breaking things
🌍 Global Reach
- Products used across 175+ countries
- 3,000+ monthly active users (LeedPDF)
- 1,500+ desktop app downloads (LeedPDF)
- 1,000+ monthly downloads (Cristalyse package)
⚡ Performance Achievements
- Sub-50ms email processing (15x faster than Gmail)
- 99% accuracy ML models with <5ms inference
- 60fps data visualizations on mobile devices
👥 Community Leadership
- 400+ member AI club president
- 89% positive feedback on technical workshops
- 370% increase in community engagement
📦 Open Source Contributions
- 450+ GitHub stars across projects
- Active contributor to Flutter ecosystem
- Technical documentation and tutorials
- BSc Computer Science (Data Analytics) – Asia Pacific University & De Montfort University
- 12+ years programming experience (started at age 12)
- President, AI Club – Led 400+ member community across 60+ nationalities
- Technical Workshop Leader – 180 average attendees, 89% positive feedback
- Product Launch Success – 15%+ increase in success rates through data analysis
- International Experience – Based in Budapest, EU work authorization ready
- English (Native) • German (Conversational) • Spanish (Elementary) • French (Beginner)
- WebGL/Three.js Advanced Techniques – Building immersive 3D portfolio experiences
- Edge Computing – Optimizing ML inference for mobile and web
- Privacy Engineering – Advanced encryption and zero-knowledge architectures
- Product Analytics – Data-driven product development methodologies
Recent Focus Areas:
- 🎯 Privacy-first architecture patterns
- 🧠 AI/ML model optimization for edge devices
- 🎨 Interactive 3D web experiences
- 📱 Cross-platform mobile development
"The products I build come from personal frustration. If I'm annoyed by something, chances are thousands of other people are too."
My approach:
- Privacy isn't negotiable: Your data belongs to you, not on someone's server
- Speed creates trust: When software responds instantly, people actually enjoy using it
- Simple beats clever: The best solution is the one people understand immediately
- Done beats perfect: Real feedback from real users beats endless internal debates
How I build:
- I write code that's easy to understand and maintain, because six months from now, I'll be that confused person trying to figure out what I was thinking
- I believe in thorough testing at every stage. Shipping fast doesn't mean shipping recklessly
- Good documentation isn't extra work, it's how you help future contributors (including yourself) hit the ground running
- Accessibility isn't a feature you add later. If it's hard to use for someone, it's not done yet
I'm always interested in connecting with fellow builders, especially around:
- Privacy-first product development
- AI/ML applications that actually help people
- Cross-platform mobile development
- Product engineering and user experience
📧 Email: reach@rudi.engineer
🌐 Portfolio: rudi.engineer (Interactive 3D experience)
💼 LinkedIn: linkedin.com/in/rudi-k
🐦 Twitter: @lofifounder
✏️ LeedPDF: leed.my
📱 DoublOne: doubl.one
📊 Cristalyse: pub.dev/packages/cristalyse
🌸 PinkRain: rain.pink
🔖 Golden Day: mygolden.day
🎬 Glucose: glucose.media
🧠 CaraML: caraml.app
🚦 Tuesdae Rush: tuesdae.games
✍️ Hashnode: hashnode.com/@lofifounder
📝 Medium: medium.com/@rudi-k
👥 Peerlist: peerlist.io/rudik
"The best way to predict the future is to build it."