Mobile app development
iOS and Android apps in React Native and Expo, with native Kotlin and CallKit modules where they matter.
REACT NATIVE · EXPO · KOTLIN · CALLKITRanak Debnath — Full-Stack Software Engineer, AI/LLM and Mobile App Developer
01 / SYSTEM
Software Engineer & Data Analyst building AI/LLM-augmented systems and full-stack products — encrypted messaging, real-time calling, payments.
CTOOMNIDEVX STUDIO
BASED INDHAKA, BD
SCROLL
02 / IMPACT
Impact, measured in production.
1,430
tests added to the messenger
COVERAGE 51% → 74%
145
API endpoints, one backend
50+ MODULES · CLEVERLYY
4,000+
users served
99% UPTIME
10
people per group call
SCALED FROM 6 · WEBRTC + MEDIASOUP
03 / PROJECTS
Four systems, four worlds.
04 / SERVICES
Tell me what to build.
Whatever you imagine — trust me, you’ll get it. As a freelance full-stack developer — or your fractional CTO — here’s what I design and build end to end, from startup MVPs to production platforms, for founders, companies and studios worldwide.
Web apps & admin dashboards
Custom web development in Next.js and React — product sites, SaaS web apps, admin consoles and data dashboards.
NEXT.JS · REACT · TAILWIND · SWRBackend & API development
Complete backends — auth, payments, jobs, real-time — in NestJS on PostgreSQL and Redis, sized to scale.
NESTJS · POSTGRESQL · REDIS · SOCKET.IOEncrypted chat apps & security
End-to-end encrypted chat apps on the Signal Protocol, encrypted on-device storage, MFA and encrypted file vaults.
LIBSIGNAL · SQLCIPHER · MFA · JWTAI integration & LLM features
AI added to new and existing apps — chatbots that answer from your own data, LLM features inside real products, and AI pipelines that turn documents into finished work.
LLM APIS · AUTOMATION · PYTHON · MLE-commerce & Stripe payments
Magento stores, Stripe payments and subscriptions, multi-currency wallets, escrow and payouts.
MAGENTO · STRIPE · WALLETS · ESCROWVideo calling & real-time apps
Group voice and video calling on WebRTC and mediasoup, live GPS tracking and push that rings a killed app.
WEBRTC · MEDIASOUP · MAPBOX · FCMData dashboards & automation
Reporting pipelines and dashboards that replace manual spreadsheet work, used daily company-wide.
SQL · SHEETS · APPS SCRIPT · BIQUESTIONS PEOPLE ASK
Can you build an app or website like the one I have in mind?
Very likely. I build end to end — mobile apps, web apps, backends, AI features, payments and e-commerce — and I have shipped encrypted messengers, booking platforms, an EdTech backend serving 4,000+ users and a Magento store. Tell me the idea and I’ll tell you how I’d build it.
Do you work with international clients as a remote freelance developer?
Yes. I run OmniDevX Studio, a cross-border studio working with clients in the UAE, South Africa and the UK from Dhaka, Bangladesh (GMT+6) — remote, in English, with regular demos. Dhaka’s working day overlaps the Gulf’s and European mornings.
Can you be our part-time (fractional) CTO?
Yes. I’m CTO of OmniDevX Studio, and I work as a fractional CTO for startups — architecture, roadmap, code review and guiding developers, while still building the product myself.
Can you build an MVP for my startup?
Yes. I scope the smallest version that proves the idea and build it end to end — mobile or web app, backend, payments and an admin panel — so you can put it in front of real users, then keep building as they arrive.
Can you build an end-to-end encrypted chat app or a video calling app?
Yes — I have built both. For Bravo Secure I built an encrypted messenger on the Signal Protocol (X3DH, Double Ratchet, Sealed Sender) with multi-device delivery, and WebRTC group voice and video calls for up to 10 people that ring even when the app is closed.
What is your tech stack?
TypeScript across the board: React Native and Expo for mobile, Next.js and React for web, NestJS with PostgreSQL and Redis for backends, WebRTC for calling, the Signal Protocol for encryption, Stripe for payments, and LLM APIs for AI features.
Can you add AI integration or LLM features to an existing product?
Yes — I have integrated AI/LLM-driven features into a production app and built an AI-assisted pipeline that generates capital-investment proposals from Excel financial models.
How do I hire you or start a project?
Email hello@ranak.bio or message me on WhatsApp. Usually I reply within a day.
05 / EXPERIENCE
Where it shipped.
DEC 2025 — PRESENT
CTO
OmniDevX Studio
- Encrypted messenger on the Signal Protocol (X3DH, Double Ratchet, Sealed Sender) with multi-device delivery and an MFA-protected encrypted file vault.
- Group voice and video calls scaled from 6 to 10 participants, with killed-app ringing via CallKit/Telecom.
- Executive Protection missions end to end: live GPS tracking, native Mapbox turn-by-turn navigation and SOS linkage.
- About 1,430 tests added, raising messenger coverage from 51% to 74%.
DEC 2024 — PRESENT
Executive Engineer
Tex Fasteners (BD) Ltd. / Tex Zippers
- AI-assisted pipeline generating capital-investment proposals from Excel financial models via DOCX XML automation.
- Performance dashboards with multi-fiscal-year comparisons, used daily company-wide, saving 1–2 hours per report.
- Reporting strategies that improved decision-making accuracy by 20% and processing speed by 25%.
AUG 2024 — NOV 2025
Senior Backend Developer
Cleverlyy (Remote)
- The complete backend: 50+ modules and 145 API endpoints serving 4,000+ users at 99% uptime.
- AI/LLM-driven features integrated directly into the production app.
- Partnered directly with the CTO on system architecture and roadmap decisions.
The stack, in depth.
- LANGUAGES: TypeScript, JavaScript, SQL, Kotlin
- MOBILE: React Native, Expo, Reanimated, Zustand
- BACKEND: NestJS, REST, Socket.IO, Jobs
- WEB: Next.js 15, React 19, SWR, Tailwind
- DATA: PostgreSQL, Redis, SQLCipher, S3
- SECURITY: libsignal, E2EE, MFA, JWT
- REAL-TIME: WebRTC, mediasoup, CallKit, Telecom
- PAYMENTS: Stripe, Escrow, Wallet, Twilio
- DEVOPS: Docker, Actions, EAS, Jest
07 / AI
Intelligence, applied.
A
AI-assisted pipeline that generates capital-investment proposals from Excel financial models, including multi-scope equipment ROI modeling.
B
AI/LLM-driven features integrated directly into the Cleverlyy production app.
C
B.Tech, CSE (Data Science, AI & ML), Lovely Professional University — First Class. Thesis: “Sonar: Mine vs. Stone Predictions.”
D
12 Coursera certifications in Machine Learning & Prompt Engineering.
[ CORE STABLE ]
08 / PHILOSOPHY
Skills matter the most, but real skills take time to build. Practice alone is not enough—you have to take on big challenges, step outside your comfort zone, and learn by solving real problems. That practical experience becomes knowledge that stays with you for life. Let people do the bitching; I’ll respond with my work. Stay loyal to what you do, stay hungry for growth and financial success.
09 / REVIEWS
In their words.
Worked with me? A few honest lines help the next founder decide — leave a rating and a review.
10 / CONTACT
Write to me.
A cross-border software studio serving clients in the UAE, South Africa and the UK — from Dhaka, Bangladesh.