Building mobile apps
from zero to production.
Specializing in Flutter, native Kotlin/Swift, and Node.js. 5+ years shipping apps at 60 FPS.
Shipped Apps & Production Systems.
A portfolio of 33 production mobile applications built across Flutter, Dart, and native Android/iOS — spanning quick commerce, on-demand services, real-time audio, and offline utilities.
Architectural Standards & Engineering Principles.
Four core practices I apply to every codebase to keep apps fast, maintainable, and resilient under real-world conditions.
Predictable State with BLoC & Riverpod
I keep UI logic dumb and state predictable. Using BLoC and Riverpod with strict repository boundaries prevents race conditions, eliminates unnecessary rebuilds, and keeps complex screens easy to debug.
Low-Latency Realtime Audio & Video
Low-latency voice and video tuned for spotty 4G/5G mobile connections. I implement adaptive bitrates, jitter buffers, acoustic echo cancellation, and dynamic token authentication using Agora RTC and WebSockets.
Fast, Lightweight Backends
Mobile-first APIs built for speed. Lightweight Node.js and Express services tuned with compound MongoDB indexes, connection pooling, and JWT auth to minimize mobile round-trips and save battery.
Native Bridges in Kotlin & Swift
When cross-platform plugins aren't enough, I drop into native code. I build custom platform channels for background GPS tracking, hardware sensors, custom audio routing, and device SDK integrations.
Professional Experience.
Senior Mobile Application Engineer
2023 — PresentRss Infotech Pvt. Ltd. · New Delhi
- ▹ Lead mobile development across Flutter client apps and Node.js APIs, keeping production crash-free rates above 99.8%.
- ▹ Built native Kotlin (Android) and Swift (iOS) platform channels for background location tracking, hardware sensors, and custom audio routing.
- ▹ Implemented low-latency audio/video features using Agora RTC and WebSockets with dynamic token authorization.
Mobile Application Engineer
2022 — 2023Shellcode IT Services Private Limited · Pune
- ▹ Built and maintained cross-platform apps for iOS and Android, establishing team conventions for Clean Architecture, BLoC, and Riverpod.
- ▹ Implemented offline-first caching using SQLite and Hive, cutting app cold startup time by 40% and eliminating scroll stutter.
- ▹ Handled app store deployments for Google Play and App Store, including release signing, privacy compliance, and staged rollouts.
Independent Mobile Engineer
2021 — 2022Independent Developer · Remote
- ▹ Developed and published 12+ utility and educational apps on Google Play, organically growing the portfolio to 48K+ active users with 4.5+ star ratings.
- ▹ Integrated payment checkouts via Razorpay and Stripe, alongside in-app monetization using Google AdMob mediation.
- ▹ Delivered custom mobile solutions directly for startup clients, taking products from initial concept to live store deployment.
Technologies & Daily Tools.
The core stack, libraries, and developer tools I use to build, test, and ship production software.
Building solid mobile apps
and solving real problems.
I build mobile apps using Flutter, native Kotlin and Swift channels, and Node.js backends. I use BLoC and Riverpod for clean state flow, keeping UI separated from business logic.
Every build is tested for production stability: 60 FPS rendering, sub-second startup, and maintaining 99.8%+ crash-free sessions across real-world devices.
I'm Pankaj Kumar — a Senior Mobile Application Engineer with 5+ years taking mobile apps from empty Git repositories to production scale on Google Play and the App Store. Shipped 12+ personal apps with 48,000+ active users, alongside 21 client production systems.
Have a project in mind or looking for a senior engineer?
I'm open to full-time senior mobile engineering roles, contract work, and technical architecture consulting. Send me an email and let's talk.