Mudassir is available for hire
Hire MudassirMudassir Raza
Verified Expert in Engineering
React Native Developer
Karachi, Pakistan
Toptal member since September 2, 2026
Bio
Mudassir is a senior React Native engineer with 6+ years of experience building cross-platform mobile apps for clients such as Cloud Coherence, eSpark Consulting Group, and TechStirr. His expertise spans React Native, TypeScript, Firebase, Node.js, GraphQL, and Apollo Client, where he thrives in an agile full SDLC environment. At Cloud Coherence, he built the React Native layer of a real-time event-driven platform, helping it scale to 100,000+ users with reliable Firestore synchronization.
Portfolio
Cloud Coherence
Firebase, React Native, Figma, Node.js, Cloud Firestore, Push Notifications...
eSpark Consulting Group
React Native, iOS, Android, Stripe, Google Maps, Push Notifications, React...
TechStirr
React Native, GraphQL, Apollo Client, React, Node.js, MongoDB, Express.js...
Experience
- MERN Stack Development - 6 years
- Firebase - 6 years
- React Native - 6 years
- Mobile Development - 6 years
- Node.js - 6 years
- REST APIs - 6 years
- JavaScript - 6 years
- React - 5 years
Work Experience
Senior Mobile Application Developer
2025 - 2026
Cloud Coherence
- Built the React Native layer of a real-time event-driven mobile platform on Firebase, supporting 100,000+ users through scalable real-time Firestore data synchronization.
- Engineered modular React Native components from Figma design specs, accelerating feature delivery by 25% per sprint and eliminating designer-to-developer handoff friction.
- Consumed real-time Firestore data through a bidirectional event-driven pipeline in the React Native app, contributing to 99.9% uptime across production environments.
- Implemented push notification systems and deep linking flows, improving user re-engagement and reducing drop-off on critical in-app journeys.
Technologies: Firebase, React Native, Figma, Node.js, Cloud Firestore, Push Notifications, Deep Linking, Event-driven Systems, Microservices, AWS Lambda, Amazon Simple Queue Service (SQS), Amazon S3 (AWS S3), Mobile Development, Postman, JavaScript, TypeScript, API Integration, Firebase Analytics, App Store Acceptance Process, User Experience (UX), User Authentication, Real-time Data, Amazon Web Services (AWS), Full-stack, Auth, AI-assisted Development, AI-generated Code, Claude Code, Front-end Development, Mobile App Development, UI Development, Responsive UI, Firebase Authentication, Mobile App Security, REST APIs, MERN Stack Development
Mobile Application Developer
2022 - 2025
eSpark Consulting Group
- Contributed to delivering and maintaining 8+ production React Native applications for iOS and Android as part of the team, collectively serving 100,000+ active users and maintaining a 4+/5 average Play Store rating.
- Reduced post-release bug backlog by 45% by building a systematic triage framework that mapped user-reported issues to root-cause patterns, cutting average fix cycle from five days to two.
- Decreased new-engineer onboarding time by 30% by authoring a design-pattern library of 20+ reusable React Native component templates adopted across three product lines.
- Integrated more than 15 3rd-party SDKs, including payment gateways (Stripe), maps (Google Maps), and push notifications, reducing custom build time by 40% per integration.
- Collaborated with cross-functional teams on agile sprint planning, translating product requirements into mobile architecture decisions with zero missed release deadlines over three years.
Technologies: React Native, iOS, Android, Stripe, Google Maps, Push Notifications, React, Node.js, Express.js, AI Chatbots, AWS Lambda, Amazon Simple Queue Service (SQS), LLM Integration, Mobile Development, Postman, LangChain, JavaScript, TypeScript, Prisma, PostgreSQL, Docker, API Integration, Firebase Analytics, App Store Acceptance Process, In-app Purchase (IAP), User Experience (UX), User Authentication, Real-time Data, Amazon Web Services (AWS), Full-stack, Web Development, Auth, Full-stack Development, Next.js, AI-assisted Development, AI-generated Code, Claude Code, Front-end Development, Mobile App Development, UI Development, Responsive UI, Firebase Authentication, Mobile App Security, Figma, REST APIs, MERN Stack Development
Lead React Native Developer
2021 - 2022
TechStirr
- Directed a team of four React Native developers through full SDLC, delivering three client applications on schedule and mentoring to reduce code-review cycle time by 50%.
- Implemented GraphQL and Apollo Client architecture, eliminating 60% of redundant API calls and reducing average data payload size by 35%, improving app load time significantly.
- Optimized app performance by profiling and resolving memory leaks and re-render bottlenecks, improving frame rate from 42 frames per second to approximately 60 frames per second on target devices.
Technologies: React Native, GraphQL, Apollo Client, React, Node.js, MongoDB, Express.js, Mobile Development, Postman, JavaScript, TypeScript, Prisma, PostgreSQL, Docker, API Integration, Firebase Analytics, App Store Acceptance Process, In-app Purchase (IAP), User Experience (UX), User Authentication, Real-time Data, Amazon Web Services (AWS), Full-stack, Web Development, Auth, Full-stack Development, Next.js, Front-end Development, Mobile App Development, UI Development, Responsive UI, Firebase Authentication, Mobile App Security, Figma, REST APIs, MERN Stack Development
React Native Developer
2020 - 2021
House of Techies
- Refactored three legacy React Native codebases to modern standards, reducing JavaScript bundle size by 28% and resolving 200+ critical ESLint violations, improving maintainability significantly.
- Collaborated with a five-engineer cross-functional team to re-architect mobile UI, improving Lighthouse performance score from 54 to 87 and reducing time to interactive by 30 – 50%.
- Built and standardized reusable React Native components and development patterns across multiple projects, reducing duplicated code and accelerating the implementation of new screens and features.
Technologies: React Native, JavaScript, Mobile Development, Postman, TypeScript, React, Node.js, Express.js, API Integration, Firebase Analytics, App Store Acceptance Process, In-app Purchase (IAP), User Experience (UX), User Authentication, Real-time Data, Full-stack, Web Development, Auth, Full-stack Development, HTML, Next.js, Front-end Development, Mobile App Development, UI Development, Responsive UI, Firebase Authentication, Mobile App Security, Figma, REST APIs, MERN Stack Development
React and React Native Developer
2019 - 2020
HNH Tech Solutions
- Developed and launched four consumer-facing React Native applications from concept through production release, including implementation, API integration, testing, and App Store deployment.
- Built reusable UI component libraries shared across applications, improving development consistency and saving an estimated 120+ development hours per project.
- Modernized two legacy applications by migrating jQuery-based functionality to React/React Native, improving time to interactive by approximately 40% and reducing ongoing maintenance complexity.
Technologies: React Native, React, Node.js, Express.js, Firebase, Push Notifications, Context API, REST APIs, Mobile Development, Postman, API Integration, In-app Purchase (IAP), User Experience (UX), User Authentication, Real-time Data, Web Development, Auth, Full-stack Development, HTML, Next.js, Front-end Development, Mobile App Development, UI Development, Responsive UI, Firebase Authentication, Figma, MERN Stack Development
Project History
DocMaster | AI-powered PDF and Document Management App
https://play.google.com/store/apps/details?id=com.docmasterDocMaster is a privacy-first React Native document management application that I independently designed, developed, and published for Android. I implemented on-device AI document chat using LLaMA 3.2, PDF viewing and editing, OCR text extraction, document scanning, image-to-PDF conversion, compression, digital signatures, and Word/Excel handling. The application processes documents locally without uploading sensitive files to a back end. I was accountable for the complete product lifecycle, including architecture, UI development, native integrations, file processing, performance optimization, testing, and Play Store release.
Stahili App
https://play.google.com/store/apps/details?id=com.stahiliStahili is a cashback and rewards app where users scan shopping receipts to earn instant cashback and complete surveys for additional rewards. I worked on this as part of a team at Cloud Coherence, alongside other React Native developers and a Node.js back-end team, with my main focus being the React Native front end. The back end uses an event-driven architecture on Google Cloud Platform, with Firestore as the real-time data layer, enabling the app to react to data changes instantly—coupon updates, survey rewards, score changes—without polling. I built out core flows, including the coupon wallet, receipt scanning, survey campaigns, and the referral system. The app is live on the Google Play Store.
ChatSpark AI Chatbot Platform
https://chatspark.io/ChatSpark is an AI chatbot platform that connects businesses with their customers across their website, Instagram, Facebook Messenger, WhatsApp, Telegram, and Slack, responding in real time in over 95 languages. Businesses index their own data—via file uploads, pasted text, or a full website crawl—and the bot answers customer questions based on that indexed content, tailored to their subscription plan. I worked on this with one other developer for a client at eSpark Consulting Group, handling the front end in Next.js and Svelte and the back end in Node.js with AWS Lambda, SQS, and S3 for async processing, and integrating LangChain for the conversational AI logic.
Education
2021 - 2024
Bachelor's Degree in Computer Science
Federal Urdu University of Arts, Sciences, and Technology (FUUAST) - Karachi, Pakistan
2018 - 2019
Mobile and Web App Development in Computer Programming
Saylani Mass IT Training - Karachi, Pakistan
Certifications
MAY 2026 - PRESENT
AWS Certified AI Practitioner
Udacity
APRIL 2019 - PRESENT
MERN Stack Development Certification
Saylani Mass IT Training
Skills
Libraries/APIs
Node.js, REST APIs, Auth, React, Apollo Client, Stripe, Google Maps, Context API, OpenAI API
Tools
Git, Postman, Claude Code, Firebase Authentication, Firebase Analytics, Figma, Jira, Xcode, Android Studio, Amazon Simple Queue Service (SQS), Prisma
Languages
JavaScript, TypeScript, GraphQL, HTML, HTML5, CSS3, Java, C#
Frameworks
React Native, Redux, Next.js, Express.js, Svelte
Paradigms
Mobile Development, Search Engine Optimization (SEO), Microservices
Platforms
Firebase, Vercel, Amazon Web Services (AWS), iOS, Android, Docker, AWS IoT, AWS Lambda, Visual Studio Code (VS Code)
Storage
Cloud Firestore, MongoDB, Amazon S3 (AWS S3), PostgreSQL
Other
MERN Stack Development, Push Notifications, API Integration, User Experience (UX), User Authentication, Real-time Data, Full-stack, Full-stack Development, AI-assisted Development, AI-generated Code, Front-end Development, Mobile App Development, UI Development, Responsive UI, Deep Linking, App Store Acceptance Process, In-app Purchase (IAP), Web Development, Mobile App Security, GitHub Actions, MVC Frameworks, LangChain, AI Chatbots, LLM Integration, Prompt Engineering, Railway, Render, Data Science, Artificial Intelligence (AI), Event-driven Systems, Llama 3, Google Gemma, Optical Character Recognition (OCR), PDF, AWS AI Practitioner, GCP
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