I build high-performance mobile apps for startups & growing businesses.
Flutter specialist in VoIP / SIP calling, WebRTC video, real-time chat, CRM workflows and Firebase-powered booking platforms — from first screen to production release.
About
The developer behind the code
Not just screens — I build apps that hold up in production, with integrations that actually work when real users pick up the phone.
I'm Sk Nayeem Ur Rahman, a Flutter developer who cares about what happens after the UI looks good. My work centres on real-time communication — VoIP and SIP calling, WebRTC video, live chat, CRM call popups and booking flows.
I've shipped 15+ production apps, including a CRM used daily by 500+ field agents. I'm currently building ServBee, an on-demand home-service platform with Firebase at its core.
My approach is simple: understand the business problem first, agree on scope in writing, then ship in milestones you can actually see and test.
core_strengths
pubspec.yamlExperience
work-history
Three years of shipping Flutter apps in a fast-moving product team — and learning what "done" really means.
Flutter Developer
@ iHelpBD Software
Led end-to-end Flutter development across 15+ production apps: a CRM used by 500+ field agents, real-time social platforms, doctor-appointment booking, e-commerce and farm-management tools. Worked directly with designers and backend engineers to ship on schedule — and stayed on after launch to fix what real users found.
Android Developer Intern
@ Next Tech BD
Hands-on Flutter and Android work during an intensive internship — contributed to CRM modules and team-collaboration tools, and picked up real production Git workflows along the way.
Projects
Apps I've built & shipped
Real products for real businesses. Hover to explore — click any card for screens, features and the full tech stack.
Services & Pricing
What it typically costs
Every project gets scoped after a short call. These are honest starting ranges — so you know roughly where you'll land before we ever talk numbers.
Feature / Integration
Add one specific capability to an app you already have.
- Firebase or REST API integration
- Payment gateway integration
- VoIP / calling feature added
- Single feature build, test & handover
Custom App / CRM
A complete app built from your requirements, start to finish.
- Full Flutter app (Android + iOS)
- Firebase or Laravel API backend
- Weekly progress updates & demos
- Store-ready build & release support
- 2 weeks of post-launch support
Ongoing / Retainer
Continued development and maintenance for a live product.
- Bug fixes & OS / SDK updates
- New features on a rolling basis
- Priority response time
- Direct line, no account managers
Skills
Dependencies I ship with
The tools I reach for every day — and how confident I am with each one.
Mobile Development
Cross-platform iOS & Android with Flutter — clean widget trees, smooth animation and layouts that hold up on every screen size.
flutter: ^3.9 — 95%
Backend Integration
Firebase (Auth, Firestore, Storage, FCM), REST APIs, real-time sync and reliable push notifications.
firebase: ^3.0 — 90%
VoIP, WebRTC & Chat
IP / SIP calling integration, WebRTC video workflows, real-time chat, call notifications and CRM-linked communication.
sip · webrtc · real-time
State Management
BLoC for large-scale apps, GetX for speed. Clean MVVM structure that stays maintainable as the product grows.
flutter_bloc: ^8.1 — 88%
UI / UX Implementation
Pixel-close from Figma. Custom animation, responsive layout and accessibility considered from the first commit.
figma_to_flutter — 85%
Version Control
Branching strategies, pull requests and code review — comfortable working inside a collaborative team repo.
git: ^2.4 — 92%
Local Storage
Offline-first with SQLite, Hive and SharedPreferences — persistence, caching and a sync strategy that survives bad networks.
sqflite: ^2.3 — 82%
Why work with me
No testimonials yet — here's what you can verify instead
I'd rather point you at something you can check yourself than put words in a client's mouth. As reviews come in on Upwork, they'll appear here — unedited, with a link to the source.
Verified Upwork profile
An ID-verified freelancer with public work history you can check directly — no cherry-picked screenshots.
view profileOpen GitHub activity
Public commit history and repositories — see how I actually structure and write code, not just final screenshots.
view github24-hour reply, always
Every message gets a reply within a day — even if it's just "still scoping this, more tomorrow." No silent weeks.
Scope in writing before we start
Fixed milestones and deliverables agreed before any code is written — no vague "we'll figure it out as we go."
Contact
Tell me about the project
WhatsApp is the fastest way to reach me — but email and LinkedIn work fine too. I reply within 24 hours, every time.
send_message.dart
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