Mudassar Hassan
Verified Expert in Engineering
Software Developer
Lahore, Punjab, Pakistan
Toptal member since April 19, 2022
Mudassar is a senior full-stack software engineer with 6+ years of expertise in building large-scale, modular web applications using Ruby, Ruby on Rails, JavaScript/TypeScript, React, Node.js, and Next.js. He is proficient in developing customer-facing applications and back-end systems with a strong foundation in SQL databases, e.g., PostgreSQL. Passionate about clean, maintainable code, Mudassar excels at leading projects, driving feature development, and collaborating across teams.
Portfolio
Experience
- Next.js - 6 years
- JavaScript - 6 years
- React - 6 years
- Ruby on Rails (RoR) - 6 years
- Node.js - 6 years
- TypeScript - 6 years
- Ruby - 6 years
- React Native - 4 years
Availability
Preferred Environment
MacOS, MacBook, Slack, Visual Studio Code (VS Code), Notion, Electron
The most amazing...
...project I've upgraded is a legacy application to the latest versions of the deprecated libraries and dependencies to unblock deployments.
Work Experience
Senior Full-stack Engineer
Toptal
- Developed a comprehensive solution to enable other services to deliver emails using SMTP protocol under the hood, offering a simple SDK interface for users to trigger notifications.
- Expanded the notification system to include SMS and WhatsApp delivery using Twilio. Implemented out-of-the-box functionality to track key metrics related to notifications, such as sent, delivered, opened, clicked, and transit issues.
- Added functionality to store all system notifications in a database and created a GraphQL endpoint to fetch, filter, and search messages for the front end.
- Scaled the service to deliver thousands of notifications and process millions of webhook requests per day from SendGrid, Twilio, and WhatsApp servers.
- Developed SDK method to generate secure, trackable links using KEM encryption.
- Developed an unsubscribe feature for marketing emails, allowing recipients to opt out.
- Developed a Generative AI engine to summarize client communications, delivering valuable insights and enhancing engagement.
- Integrated with Gmail’s server to authorize, fetch, and store emails for specific recipients, ensuring smooth email management within the system.
- Set up Grafana dashboards to show the number of emails sent, delivered, opened, and clicked. Registered alerts for an increase in spam rate and a decrease in delivery and open rate, helping our engineer respond quickly to potential system issues.
- Developed a Slack bot to mark messages as "must read," sending daily reminders until acknowledged. Added "must do" functionality, allowing recipients to check off tasks after completion. It allowed hundreds of users to be more productive.
Software Engineer
MonteDelGallo
- Implemented a calendar view in an existing MERN application to display the availability of cars on specific dates and added functionality to filter results by car name, date range, etc.
- Developed the back end of a library system from scratch. It helped to streamline manual processes and improved access. It also enabled real-time reporting.
- Improved test coverage of an existing MERN application to an extent where we felt confident shipping new features.
- Designed and implemented RESTful APIs using Express.js to handle CRUD operations. Managed data storage and retrieval with MongoDB, ensuring efficient queries and indexing. Implemented user authentication and authorization with JWT.
- Built responsive UI components using React and TailwindCSS, enhancing UX with dynamic content. Utilized state management with Redux to manage application state across components. Integrated API calls to connect front- with back-end services.
- Conducted unit and integration testing. Deployed the application and ensured continuous integration/continuous deployment (CI/CD) practices.
Software Engineer
Online Freelance Marketplace
- Implemented content security policy and HTTP strict transport security for the website to mitigate cross-site scripting (XSS) and man-in-the-middle attacks.
- Changed the integration of Google Tag Manager to a nonce-based approach to confine with CSP.
- Reduced unused JavaScript by analyzing the website with the help of Lighthouse and Chrome Coverage.
- Developed features and revamped the password reset flow of the recruiting application.
- Managed a team of two engineers to accomplish tasks and features.
Software Engineer
Devsinc
- Fixed the data syncing problem of a time and expense management system with QuickBooks by implementing Sidekiq jobs with a proper retries mechanism, drastically reducing customers' complaints.
- Resolved bugs in a legacy mobile app and upgraded outdated libraries, which unblocked feature shipping.
- Used caching to reduce database read calls in the overall system by leveraging page caching for static pages and Redis for custom caching. This helped to serve more concurrent users in the same system.
- Streamlined local setup of service, which had a number of manual steps by automating the process, resulting in great developer efficiency.
- Proposed performance and security enhancements for the back end, improving application efficiency.
Junior Software Engineer
SenSights.AI by LocateMotion
- Developed the user profile management and authentication UI and integrated them with the back end.
- Refactored the code to support the reusability and consistency of components across the entire project.
- Investigated and fixed bugs and logged them on a Jira board.
Experience
Minute7
https://www.minute7.com/The front end of the application was developed in React and the back end with Ruby on Rails. I improved scalability issues in the QuickBooks syncing process with the quickbooks-ruby driver, assisted in migrating legacy mobile application code to the latest framework versions, and shipped several new features in the application.
HundredX
https://hundredx.com/Swvl Travel
Education
Bachelor's Degree in Software Engineering
Punjab University College of Information Technology - Lahore, Pakistan
Skills
Libraries/APIs
React, Node.js, React Query, REST APIs, Google Calendar API, Stripe, Stripe API, Stripe Connect, jQuery, API Development, Rails Engines, D3.js, AWS Amplify, Vue, Shopify API, Sidekiq, Vue 3, OpenAI API, react-spring, Ggplot2, MobX, React Testing Library, Matter.js, Recharts, Puppeteer, Liquid, React Redux, TanStack Table, Microsoft Authentication Library (MSAL), AG Grid, Framer Motion
Tools
Git, RSpec, SendGrid, Figma, Ngrok, AWS Batch, Amazon Simple Notification Service (SNS), Kafka Connect, Kafka Streams, Auth0, GitHub, Expo, Webpack, Grafana, Mongoose, Prisma, Firebase Authentication, Amazon Simple Queue Service (SQS), Terraform, Amazon Elastic Container Service (ECS), Drizzle ORM, Shadcn, NGINX, Docker Compose, RabbitMQ, Charles Proxy, Canvas, Cron
Languages
JavaScript, Ruby, CSS3, TypeScript, HTML5, GraphQL, CSS, HTML, SQL, Python, SCSS, Sass, ECMAScript (ES6), Go, Java, PHP
Frameworks
Ruby on Rails (RoR), Next.js, Redux, Tailwind CSS, React Native, Angular, Bootstrap, AngularJS, Vanilla JS, NestJS, Nuxt.js, Bootstrap 3, Jest, Cypress, Express.js, Selenium, Alpine, Electron, Ruby on Rails 5, MUI CSS
Paradigms
REST, Automated Testing, Responsive Web Design (RWD), E2E Testing, DevOps, Event-driven Architecture, Lambda Architecture, Microservices, Automation, Mobile Development, Search Engine Optimization (SEO), Unit Testing, Design Patterns, Object-oriented Programming (OOP)
Platforms
Docker, Apache Kafka, Amazon Web Services (AWS), Google Cloud Platform (GCP), AWS Lambda, Webflow, Firebase, Heroku, Storyblok, Sanity Studio, Twilio, Webflow CMS, Kubernetes, Vercel, AWS IoT, Shopify, WordPress, Contentful, Ethereum, Azure, Blockchain, iOS, Netlify
Storage
PostgreSQL, MySQL, Redis Cache, Databases, NoSQL, Amazon DynamoDB, Data Pipelines, Google Cloud, Database Architecture, MongoDB, Amazon S3 (AWS S3), Datadog, MariaDB, Redis, Elasticsearch
Industry Expertise
Accounting, Banking & Finance
Other
Bootstrap 4, Front-end Development, Front-end, Architecture, Bots, Single Sign-on (SSO), APIs, Payment Gateways, Full-stack, Software Architecture, Technical Leadership, Full-stack Development, Video Streaming, Back-end Development, Video management System, API Integration, System Architecture, User Interface (UI), Web Development, Bootstrap 5, DOM, Web Applications, WebSockets, Tailwind UI, Content Delivery Networks (CDN), Startups, Data Modeling, Infrastructure, Data Visualization, Monorepos, Figma to React, Back-end, User Experience (UX), MERN Stack, Third-party APIs, eCommerce, Content Management Systems (CMS), Google Calendar, Dashboards, Caching, UI Development, Large Data Sets, Server-side Rendering (SSR), Scaling, MVC architecture, Optical Character Recognition (OCR), Accelerated Mobile Pages (AMP), Email, Gmail, FastAPI, React Components, Front-end Architecture, Communication, SEO Tools, Google SEO, Video Conferencing, Video APIs, Chatbots, Web3, Finance, Fund Management, Supabase, Chrome Extensions, OAuth, CI/CD Pipelines, Serverless, GitHub Actions, OpenAI, Kinde, Cloud Infrastructure, Amazon RDS, ECS, Real-time Communication (RTC), Generative Artificial Intelligence (GenAI), Large Language Models (LLMs), Machine Learning, Leadership, Apple Pay, foodics, Headless CMS, Headless UI, Monday.com, Headless WordPress, NetFlow, Software Design, Minimum Viable Product (MVP), Strapi, Artificial Intelligence (AI), CRM Implementation (Salesforce), Design, Storybook, Web Application Firewall (WAF), Solution Architecture, Web Scraping, Browser Automation, Vectorization, browserbase, Ethical Hacking, mitmproxy, WYSIWYG Web Builders, Accessibility, WCAG, Data Build Tool (dbt), Apache Superset, Image Processing, Chakra UI, Vite, Zustand, NextAuth.js, Radix UI, Real-time Data, Cloud, Drag & Drop, Lovable.dev, Responsive Design, A11Y
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