Android Developer
Rahul Kumar builds Android apps that work when the network doesn't.
Three years shipping Kotlin & Java applications end to end — offline-first sync, real-time queues, geofenced attendance, and maps-based navigation, used by pubs, government fleets, and maritime surveyors alike.
01 — About
Profile
Results-driven Android Developer with three years of experience designing, developing, and maintaining high-quality mobile applications. Proficient in Kotlin and Java, with hands-on experience across the Android SDK, RESTful APIs, and MVVM / Clean Architecture.
Comfortable owning a feature end to end — from requirement analysis and architecture through deployment and production support — and collaborating closely with backend and QA teams to ship reliable, user-focused software.
02 — Skills
Technical stack
Organized the way a project's source tree is — expand a folder to see what's inside.
▶ languages/ 3 items
▶ android-framework/ 10 items
▶ networking/ 4 items
▶ tools-platforms/ 7 items
▶ integrations/ 5 items
03 — Experience
Where I've worked
Android Developer
NRT Consultancy Services Pvt. Ltd. — Ranchi, Jharkhand
Oct 2023 — Present
- Developed scalable Android applications using Kotlin and Java, following MVVM and Clean Architecture.
- Built modern, responsive UIs with Jetpack Compose and XML, aligned with Material Design principles.
- Integrated RESTful APIs using Retrofit and OkHttp for efficient data communication.
- Designed an offline-first architecture with reliable two-way data synchronization for seamless online and offline operation.
- Implemented secure local data management and caching strategies to strengthen reliability.
- Integrated Firebase Analytics, Crashlytics, and push notifications for monitoring, engagement, and crash reporting.
- Owned features end to end, from requirement analysis through deployment and production support.
04 — Projects
Shipped applications
Four production apps across four very different constraints — real-time, offline-first, geolocation, and biometrics.
Smart Music Queue
OneTheme — England (Offsite)
Nov 2025 — Present
An Android app letting pub and bar patrons queue their own songs on a venue's shared sound system. Spotify SDK/API power secure venue and user authentication and playback; a real-time queue shows each listener their position and live status, alongside map-based discovery of nearby venues by genre and vibe.
HRMS Android App
OneTheme — 20+ branches
Dec 2024 — Sep 2025
A location-based attendance system combining real-time face recognition, GPS verification, and biometric unlock to eliminate proxy attendance. Role-based dashboards serve employees, managers, and HR with leave approval, payslips, holiday calendars, and remote manager sign-off, synced through REST APIs.
Govt. Ride-Hailing App
State Government (Offsite)
Sep 2024 — Present
A ride-hailing application for booking government taxis and vehicles, built in Kotlin and Java. TomTom's Maps API and SDK power route-finding and turn-by-turn navigation between pickup and destination, with Retrofit handling live ride tracking and status updates.
Bunker Survey App
Maritime client — Malta, EU (Offsite)
Jan 2024 — Aug 2024
An offline-first Android app for maritime fuel surveyors working in low-connectivity conditions. Task assignment, survey workflows, and structured data collection run on local SQLite storage, with custom fuel calculation logic built to bunker survey standards and automatic two-way sync once connectivity returns.
05 — AI & Mobile
Bringing AI on-device
Native Android already leans on ML for face recognition and geofencing. The next layer I'm building toward is conversational and retrieval-driven AI inside the same apps.
On-device & applied ML
Face recognition and biometric verification already run in production in the HRMS app. Extending this with TensorFlow Lite and ML Kit for on-device inference — keeping latency low and data local.
LLM-powered assistants
Designing conversational features — in-app help, smart search, and support chat — backed by LLM APIs (Claude, GPT, Gemini), wired into Android through Retrofit/OkHttp the same way any REST integration is built today.
RAG for contextual answers
Exploring retrieval-augmented generation to ground assistant responses in a venue's own data — think a music-queue app that answers "what's playing near me" from live app state instead of a static model.
Where it fits my apps
Music discovery, HR self-service Q&A, and ride-support chat are the natural next features across my existing projects — each already has the structured data an LLM/RAG layer would sit on top of.
These are skills I'm actively building and applying to side extensions of the projects above, alongside day-to-day native Android work.
06 — Education
Academic background
Bachelor of Technology, Computer Science
Bihar Engineering University — Patna, Bihar
CGPA: 8.17
Aug 2019 — Sep 2023
07 — Contact
Let's work together
Open to Android developer roles and freelance builds. The fastest way to reach me is email or a call — the form below opens a pre-filled email for you.