Samuel Mpwanyi
Verified Expert in Engineering
JavaScript 6 Developer
Kampala, Central Region, Uganda
Toptal member since July 21, 2025
Full-stack JavaScript developer with 8+ years of experience, now transitioning into consultancy. I enjoy working directly with stakeholders and product teams to turn ideas into real products. I’m currently building thetravella.app and helping early-stage startups overcome scaling issues, heavy-traffic challenges, and database performance bottlenecks.
Portfolio
Experience
- JavaScript 6 - 8 years
- Node.js - 8 years
- Vuex - 8 years
- JavaScript MVC - 8 years
- TypeScript - 7 years
- React - 6 years
- Google Cloud Platform (GCP) - 4 years
- Next.js - 3 years
Work Experience
Senior Front-end Developer
CROWDBOTICS
- Led the end-to-end integration of an AI-powered assistant using OpenAI’s RAG architecture, enabling users to retrieve PRD information and execute actions via natural language, reducing manual documentation lookup time by over 60%.
- Refactored legacy front-end components into modular, reusable blocks using TypeScript and modern React patterns, reducing code redundancy and improving maintainability across projects.
- Implemented end-to-end testing using Jest and Cypress, increasing front-end test coverage from 45% to over 80%, and reducing post-deployment bugs by 50%.
- Optimized load times on interactive views by implementing code-splitting and lazy loading strategies, leading to a 25% decrease in initial render times.
- Mentored two junior front-end engineers on architecture decisions, state management, and component testing, accelerating their readiness for client-facing work within three months.
Senior Front-end Developer
Liquality
- Implemented key UI features for Liquality's Web3 wallet using Vue and TypeScript, enhancing user experience for over 10,000 wallet users across browser extension and desktop platforms.
- Integrated blockchain interaction flows using Ethers.js, enabling users to send, receive, and swap crypto assets with improved reliability and lower error rates.
- Built and tested Chrome Extension UI components using reusable Vue patterns and scoped styling, improving maintainability and deployment consistency.
Senior Full-stack Developer
Patient Studio
- Implemented secure VISA payment processing for both card-present and card-not-present scenarios using Payroc and the Serverless Framework on AWS, enabling seamless client billing and reducing manual reconciliation time by 70%.
- Developed and deployed an eFax messaging tool using the Documo API, allowing clinics to send and receive digital faxes, which improved communication speed across practices by over 50%.
- Architected scalable back-end models using Node.js, TypeScript, and GraphQL, ensuring high reliability for the platform’s scheduling, documentation, and billing systems.
- Leveraged AWS services, including Lambda, DynamoDB, and S3, to support a highly available infrastructure with minimal DevOps overhead.
- Integrated Elasticsearch to enable fast, complex queries for patient records and communication logs, enhancing platform responsiveness and improving user satisfaction.
- Deployed a serverless back-end architecture that scaled automatically with usage, contributing to an infrastructure cost savings of approximately 25%.
- Participated in agile sprints and code reviews, maintaining high standards of code quality and documentation across the back-end team.
Senior Front-end Developer and Team Lead
BPO Seats
- Led the development of a video conferencing feature using WebRTC and Amazon Kinesis Video Streams, enabling seamless remote interviews and meetings for over 1,000 clients and staff across multiple BPO facilities.
- Spearheaded the implementation of an encryption-enabled IndexedDB module to improve client-side data security and application reliability, which reduced browser-side data corruption incidents by 40%.
- Guided a team of over 40 developers and conducted peer evaluations, mentoring, and weekly code reviews, resulting in improved code quality and faster onboarding of new team members.
- Optimized front-end performance by implementing lazy loading, asset bundling, and state management improvements, reducing load times by up to 30% across major views.
- Built internal dashboards and booking management tools for clients to manage seat leasing, which enhanced visibility and reduced support tickets by an estimated 25%.
- Coordinated closely with stakeholders across multiple departments, ensuring technical solutions aligned with business goals and operational needs.
Experience
SmartPOS
https://smartposcloud.app/TheTravella
https://play.google.com/store/apps/details?id=com.prodevkampala.travella&hl=enEducation
Bachelor's Degree in Computer Science
Ndejje University - Kampala Uganda
Skills
Libraries/APIs
Node.js, Vuex, Vue 2, React, Vue, Vue 3, Google Maps API, Stripe, React Redux, REST APIs, OpenAI API, Twilio API, WebRTC, Stripe API
Tools
Slack, GitHub, Jira, GitLab, Mattermost, Git, Create React App, JSX, ChatGPT, Stripe Checkout, Figma, Webpack, Shadcn, Expo, MQTT, Atlassian
Languages
JavaScript 6, TypeScript, GraphQL, JavaScript, CSS, HTML5, SQL, TypeScript 3, HTML, SCSS
Frameworks
JavaScript MVC, Redux, Tailwind CSS, Express.js, Serverless Framework, Laravel, Electron, React Native, Next.js
Paradigms
Agile Software Development, Database Design, UI Design, Responsive Web Design (RWD), UX Design, API Architecture, Back-end Architecture, Asynchronous Programming, DevOps, Microfrontends
Platforms
MacOS, Visual Studio Code (VS Code), Vercel, Firebase, Web, Heroku, AWS IoT, Google Cloud Platform (GCP), Amazon Web Services (AWS), Twilio, Docker, Kubernetes, Android, iOS
Industry Expertise
Web Design
Storage
PostgreSQL 10, Redis, PostgreSQL, MySQL, MongoDB, Elasticsearch
Other
SaaS, Software Development, System Architecture, Web Development, Full-stack, Performance Optimization, User Experience (UX), User Interface (UI), Application Security, Documentation, Code Auditing, Front-end Development, Algorithms, APIs, Full-stack Development, Front-end, Debugging, Supabase Auth, API Design, API Integration, API Testing, Payment Gateways, Back-end, Security, WebSockets, System Design, Architecture, CI/CD Pipelines, Cloud Hosting, Real-time Data, GitHub Actions, Quality Assurance (QA), Retrieval-augmented Generation (RAG), Ethers.js, Chrome Extensions, Supabase, Flutterwave, Mobile App Development, Serverless, AWS Cloud Architecture, Artificial Intelligence (AI), Web Scraping, Augmented Reality (AR), OpenAI, Large Language Models (LLMs), Row-level Security (RLS), Headless CMS, AI Agents, AI Assistants, Web3, LangChain, Airtable
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