
Muzammil Husnain
Verified Expert in Engineering
Software Developer
Dallas, TX, United States
Toptal member since May 30, 2023
Muzammil is a skilled and responsible developer who excels in crafting complex applications and brings a wealth of experience. His expertise spans diverse technical and business domains, honed over eight years. He values effective communication, organization, and collaboration and thrives in team environments. Muzammil embraces challenges and utilizes his creativity to discover innovative solutions and tackle challenges head-on.
Portfolio
Experience
- Android - 8 years
- Java - 8 years
- Clean Architecture - 8 years
- Unit Testing - 8 years
- Git - 7 years
- Android Jetpack - 7 years
- Model View ViewModel (MVVM) - 7 years
- Kotlin - 6 years
Preferred Environment
Kotlin, Java, Clean Architecture, Agile Sprints, Android, Unit Testing, Android Jetpack, Firebase, REST APIs, Jetpack Compose, Claude API, Claude Code, Dashboards, Python, Web Development, Financial UX, Artificial Intelligence (AI), AI Design, AI Programming, Minimum Viable Product (MVP), AI Agents, AI Copilots, Agentic RAG Systems, Code Review, Docker, IT Security, Platforms, System Design, Kubernetes, SaaS, Microservices Architecture, Microservices, Multi-tenant SaaS, Business Rules Engine, Compliance, Enterprise Integration Patterns (EIP), Regulated Industries, Multi-tenant Architecture, Agentic AI, Full-stack, Full-stack Development, Leadership, Role-based Access Control (RBAC), Solution Architecture, Multitenancy
The most amazing...
...things I've done were developing a Nike eCommerce application and leading an Android team to implement video calls using WebRTC for Convo.
Work Experience
Senior Flutter Developer
Lucid Finance
- Built and shipped an AI-powered personal finance iOS/Android app backed by Firebase Cloud Functions and Firestore, delivering Plaid bank sync, and a provider-agnostic AI layer.
- Engineered Plaid end-to-end: a webhook-triggered Sync v2 backfill (TDD, 102 tests), iOS/Android OAuth redirects, and a production-access compliance program with an automated field-access gate.
- Shipped a 4-tier subscription module across 11 Cloud Functions with Apple IAP, Stripe lifetime entitlements, Firestore-enforced access control, and a B2B employer seat-claim path.
- Hardened security with auto-lock, biometric/server-verified PIN, and a codebase audit that fixed a critical Firestore token-exposure flaw; ran RCAs and a Riverpod 3 migration for stability.
Senior Native Android Developer
Zed Financial, Inc.
- Led the end-to-end development of the Zed Card Android app, owning the architecture, implementation, and delivery of a fully functional fintech product from scratch.
- Established Compose-based UI foundations and MVVM-C navigation patterns to support rapid iteration and scalable feature development.
- Ensured a high-quality engineering foundation through modularization, documentation, and best-practice Android development workflows.
- Built and launched a modern Android banking app from scratch using Kotlin, Jetpack Compose, MVVM-C, and Room, delivering a scalable fintech experience for a 150,000+ waitlisted user base.
Senior Android Engineer
Freedompay
- Designed and maintained modular Android SDKs and libraries (CX, Freeway, AFCC) used by thousands of merchants globally.
- Built internal SDKs for POS devices (Castles, Axium, Tetra, Toast), improving onboarding speed by 30% and device compatibility.
- Implemented secure payment workflows with encryption and tokenization, achieving full PCI compliance.
- Mentored Android engineers and defined SDK architecture standards, improving team velocity and code quality.
- Drove performance profiling and debugging, reducing transaction errors by 25% across merchant networks.
Android Team Lead
PNC
- Led a team of five engineers in migrating a multi-module legacy app to micro-app architecture using MVVM-C, Jetpack Compose, and clean architecture.
- Defined coding standards and architecture guidelines adopted across the Android team, improving maintainability and delivery speed.
- Delivered high-visibility features (card management, card-free ATM, control hub, help center, branch locator), enhancing self-service for millions of customers.
- Optimized CI/CD pipelines and modularization, reducing release cycles by 20%.
- Collaborated with product and architecture teams to translate business requirements into scalable mobile solutions.
Android/Kotlin Developer
The Weather Group - Main
- Developed and delivered new features across three OTT apps for Android mobile, tablet, Android TV, and Fire TV, enhancing user engagement and platform reach.
- Contributed to CI/CD pipeline setup using GitHub Actions for Local Now, Synergy, and HBCU GO, improving build automation and deployment efficiency.
- Tracked, prioritized, and resolved bugs and feature requests using Jira, ensuring timely delivery and high-quality releases.
Senior Android Engineer
Nike
- Contributed to Nike’s global eCommerce app, optimizing cart, checkout, payments, and order history modules used by millions.
- Delivered international payment flows for the Korean market, enabling market expansion.
- Migrated legacy Java code to Kotlin, modernizing the codebase for testability and maintainability.
- Led cross-functional bug triage and PR review process, reducing backlog by 30% and improving code quality.
- Managed release coordination across distributed teams in three time zones, ensuring timely feature delivery.
Senior Android Developer | Team Lead
Convo
- Built and led a 7-member Android team for a global collaboration platform.
- Delivered high-impact features for H&M, driving thousands of new users and client satisfaction.
- Implemented Google Maps, geolocation, email workflows, and advanced chat.
- Architected and led implementation of the in-house solution for audio/video calls using WebRTC.
- Modernized legacy Java codebase to Kotlin and MVVM, improving performance, maintainability, and scalability.
- Streamlined CI/CD and Gradle builds, ensuring smooth production releases.
- Reduced app crashes and multithreading issues by 40% through code re-engineering.
Android Developer
Ideofuzion
- Led a team of 2 in integration with Fitbit, Garmin, Google Fit, and Samsung Health.
- Revamped the application on modular bases and wrote unit tests that increased the app's performance and stability.
- Developed scalable Android apps using Kotlin/Java, Room, REST APIs, and modern architectures.
Android Developer
Nextin
- Developed a desktop app with a user-friendly dashboard to input designs and make configurational changes. The app integrated design inputs and configurations into a template project to generate a fully functional Android application.
- Worked on Android smartwatch faces and a companion app to apply watch faces on connected Android watches. Used Android smartwatch operating system and implemented REST APIs.
- Developed a white noise mindfulness application that provided multiple white noises and multiple features around it. Implemented caching using SQLite databases and REST API.
- Learned and implemented libGDX for a live wallpapers project.
Experience
Nike Retail Application
https://play.google.com/store/apps/details?id=com.nike.omegaConvo | Collaboration Platform for Work
http://www.convo.comYAS | Einfach Gesünder Leben
https://play.google.com/store/apps/details?id=com.yaslife.appQuran App
Calm Ambience
WatchCraft
Paperscape | Live Wallpaper
APK Factory
Education
Master's Degree in Data Science
Maharishi International University - Fairfield, Iowa, United States
Bachelor's Degree in Computer Science
Mohammad Ali Jinnah University - Islamabad, Pakistan
Skills
Libraries/APIs
REST APIs, Retrofit, Camera API, Camera2 API, Google Maps SDK, Google Maps, Jetpack Room, RxKotlin, MockK, Stripe, Stripe API, Twilio API, Claude API, Android Support Library, WebRTC, Google Maps API, Proguard, Garmin API, Fitbit API, Android Volley API, RxJava, Socket.IO, GCM, WorkManager API, Android Architecture Components, RxJava 2, Retrofit 2, AndroidX, Kotlin Flows, Coinbase API, Firebase Web SDK
Tools
Git, Android Jetpack, Gradle, Android Studio, Jira, Apache Maven, GitLab CI/CD, Claude, ChatGPT, ExoPlayer, Fastlane, Auth0, Claude Code, Figma, Android Auto, Bitbucket, Firebase Cloud Messaging (FCM), GitHub, Jenkins, Xcode, CircleCI
Languages
Kotlin, Java, Dart, TypeScript, Python, XML, Processing, HTML, CSS, JavaScript
Frameworks
Android SDK, Flutter, Next.js, Business Rules Engine, Dagger, Ant Design, LibGDX, Mockito, Robolectric, Espresso, Dagger 2, Material UI, JUnit, Kotlin Serialization
Paradigms
Clean Architecture, Unit Testing, Design Patterns, Model View ViewModel (MVVM), Mobile Development, Agile, Scrum, Testing, Reactive Programming, UI Design, Continuous Integration (CI), HIPAA Compliance, B2C, DevOps, Microservices Architecture, Microservices, Role-based Access Control (RBAC), Model View Presenter (MVP), Model View Intent (MVI), Object-oriented Programming (OOP), Agile Software Development, Dependency Injection, Android Material Design, Kanban, MVC Design
Platforms
Android, Mobile, Amazon Web Services (AWS), iOS, Docker, Kubernetes, Firebase, Android TV, Android Watch, Eclipse, NetBeans
Storage
PostgreSQL, Cloud Firestore, JSON, Databases, SQLite, RoomDB, JSON/XML Schemas
Other
Agile Sprints, CI/CD Pipelines, Android Architecture, SDKs, Apps, Architecture, Mobile App Development, APIs, Processing & Threading, Performance, Minimum Viable Product (MVP), Android Development, User Interface (UI), RTL, Internationalization, Localization, Google Pay, Front-end, A/B Testing, Networking, TCP/IP, Multithreading, Mobile Apps, Mobile Applications, Maps, Accessibility, API Integration, User Experience (UX), Pixel Perfect, Software Architecture, Early-stage Startups, Push Notifications, AOSP, POS, Point of Sale, USB, Embedded Systems, RESTFul APIs, Fintech, WebSockets, Android Performance Optimization, Android App Development, Google Play Store, MVVM-C, Artificial Intelligence (AI), Cursor AI, Chatbots, Large Language Models (LLMs), Amazon Fire TV, Technical Leadership, Offline Data Synchronization, Barcode Scanners, AI Automation, Kotlin Multiplatform, Kotlin Multiplatform Mobile (KMM), Large-scale Projects, Online Payments, Consumer-facing Products, Concurrency, Performance Optimization, App Store Connect, Anthropic, OpenAI, Dashboards, Web Development, Financial UX, AI Design, AI Programming, AI Agents, AI Copilots, Agentic RAG Systems, Code Review, IT Security, Platforms, System Design, SaaS, Multi-tenant SaaS, Compliance, Enterprise Integration Patterns (EIP), Regulated Industries, Multi-tenant Architecture, Agentic AI, Coding, Full-stack, Full-stack Development, Leadership, Solution Architecture, LiveStream, Video Livestreaming, Jetpack Compose, eCommerce, Payment APIs, Voice Chat, Firebase Crashlytics, GitHub Actions, HTTP Live Streaming (HLS), Streaming, Back-end Development, Android MDM, MDM, Multitenancy, Algorithms, Data Structures, Big Data, Machine Learning, Troubleshooting, Bug Fixes, Google Fit, Samsung, Coroutines, XMPP, Spring Dependency Injection (DI), Material Design, Room, Over-the-top Content (OTT), Firebase Cloud Functions, Full-stack Design, Back-end, Firebase Hosting
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
Share your needs
Choose your talent
Start your risk-free talent trial
Top talent is in high demand.
Start hiring