The developer
behind the apps
I'm Shahzaib Hassan, a senior Flutter developer based in Pakistan. For four years I've been building iOS and Android apps that people pay for, chat in, and rely on, and fixing the ones that stopped working.
- Based in
- Pakistan (UTC+5)
- Currently
- Senior Flutter Developer at Code Encoders
- Shipping Flutter since
- 2022
- Open to
- Freelance projects and remote roles

How I got here
I studied Computer Science, and during my internship at Rex Technologies in 2022 I built my first real Flutter app, ExamConnect, on my own. It went on to pass 10,000 downloads. Flutter won me over because a single codebase gave me Android and iOS at once, which meant I could build faster and own the whole app. Four years on, I specialise in real-time chat and messaging apps for startups and businesses.
I started building Flutter apps professionally at Rex Technologies in 2022. That's where I learned what production really means: chasing crashes reported by users, fixing screens that stuttered on cheaper Android phones, and turning designs into UI that matched them pixel for pixel.
In 2024 I joined Code Encoders as a senior Flutter developer. Most of what I know about the hard parts of mobile comes from there: subscriptions that have to agree across Apple and Google, maps full of live data, wallets created from a Google login, and identity checks that can't feel like paperwork.
The products I work on
Most of my work falls into four groups: social and dating apps with real-time chat and presence, marketplaces with several kinds of users in one app, fintech and Web3 products with payments and verification, and apps built around location. They look different, but they share one trait: they only work if the data underneath is live, correct, and fast.
How I approach engineering
I plan state, data flow, and integrations before I build screens. It feels slower in week one and saves months later, because the tenth feature should be as easy to add as the first. I choose boring, well-supported tools over clever ones, and I'd rather ship a smaller app that never crashes than a bigger one that does.
How I approach an existing codebase
When I take over an app, I don't start by rewriting it. I read it, run it, and find out where it actually hurts: crash reports, slow screens, flaky builds, state that's shared in ways nobody intended.
Then I fix what affects users first and improve the structure gradually, so the app keeps shipping while it gets healthier. A full rewrite is sometimes the right call, but it should be a decision backed by evidence, not a reflex.
What I care about
Stable beats clever.
An app that loads fast and never crashes earns more trust than a feature that impresses in a demo.
Architecture before screens.
Good structure is what keeps a growing app from slowing every release down.
No surprises.
Clients always know what shipped, what's next, and what's at risk, in plain language.
Who I work best with
Founders
Who have a clear problem and want a developer who'll push back when something won't work.
Product teams
With a live app that needs a dependable Flutter owner.
Agencies
That need a senior developer they can put in front of a client.
Companies hiring
For a Flutter role where shipping and stability matter more than buzzwords.
What clients say
Turned the idea into a smooth, polished product.
He took ownership of the mobile app, handled complex features like real-time chat, location-based discovery, matching and subscriptions, and turned the idea into a smooth, polished product. His communication, problem-solving and attention to detail made a real difference throughout the project.
A strong focus on quality and user experience.
Working with Shahzaib on StyleBite was a great experience. He understood the requirements well, communicated clearly, and delivered the Flutter app with a strong focus on quality and user experience.
Reliable, responsive and professional.
It was great working with Shahzaib. He was reliable, responsive, and handled the Flutter development professionally, delivering a smooth and well-built app.
Experience
- Jan 2024 to now
Senior Flutter Developer, Code Encoders
- Lead Flutter development on consumer and business apps, from design to App Store and Google Play release
- Built in-app subscriptions and paywalls with RevenueCat and native store billing
- Built live tracking, venue discovery, and location features with Google Maps and Places
- Implemented Apple, Google, and Web3Auth sign-in, plus DIDIT KYC and KYB verification flows
- Reduced app startup times and kept releases passing App Store review
- Jun 2022 to Jan 2024
Flutter Developer, Rex Technologies
- Built and maintained production Flutter apps alongside the design team
- Fixed crash and rendering bottlenecks to keep the UI smooth at 60fps
- Built responsive, pixel-perfect components across iOS and Android
- Feb 2022 to May 2022
Flutter Intern, Rex Technologies
Built ExamConnect solo, a study and chat app for medical students that passed 10,000 downloads.
Toolkit
Core
6 toolsData and real-time
6 toolsIntegrations
6 toolsShipping
4 toolsLet's talk about your app
You'll work directly with me, from the first call to the release.
the apps I've built