Saad Ul Hassan
Verified Expert in Engineering
JavaScript Developer
Rawalpindi, Punjab, Pakistan
Toptal member since July 8, 2025
I build software that moves money, moves people, and moves businesses forward. In 7 years, I've engineered solutions across fintech, e-commerce, transportation, and construction, adapting rapidly to new domains while delivering exceptional results. I speak fluent React, Node.js, Python, and Django, but more importantly, I speak business. Whether architecting from scratch or leading teams through critical launches, I deliver software that drives revenue, not just features.
Portfolio
Experience
- JavaScript - 9 years
- TypeScript - 8 years
- Node.js - 8 years
- React - 8 years
- Next.js - 8 years
- PostgreSQL - 8 years
- NestJS - 5 years
- Django - 5 years
Work Experience
Senior AI Engineer
Emerge Haus LLC
- Architected and delivered production-grade AI, back-end, and full-stack solutions for AgentPress clients, working approximately 40 hours per week across TypeScript, Python, React, Next.js, Node.js, PostgreSQL, Redis, and AWS.
- Achieved an approximately 99% successful posting rate across more than 20 construction document and transaction workflows, including estimates, subcontracts, change orders, change requests, and subcontract invoices.
- Enhanced Local Falcon’s AI-powered local-search intelligence platform by developing AI scan workflows, automated analysis reports, geolocation enrichment, brand identification, sentiment analysis, and generative search optimization features.
- Optimized location lookup and enrichment workflows against a PostgreSQL dataset containing approximately 40 million business-location records, improving the reliability and scalability of Google Place ID resolution.
- Improved AI report accuracy by filtering hallucinated brands and invalid zero-grid-point results before initiating place-ID lookups and web-scraping operations, reducing unnecessary processing and external API usage.
- Diagnosed and resolved complex production issues across authentication, proxy infrastructure, API integrations, database queries, AI tool calls, and cloud deployments using request tracing, activity monitoring, and structured debugging.
- Designed and optimized REST and XML API integrations, database schemas, asynchronous processing pipelines, and caching strategies for performance-sensitive, business-critical applications.
- Supported cloud infrastructure and deployment workflows using Docker, AWS ECS, Application Load Balancers, Terraform, Render, CI/CD pipelines, and environment-specific configuration management.
- Stabilized and advanced multiple client products through production debugging, architectural improvements, performance optimization, automated testing, and hands-on ownership of high-priority releases.
PayPal Checkout Developer
Joshua Routh
- Engineered PayPal payment pipeline integration that streamlined checkout processes and reduced payment abandonment across the e-commerce platform.
- Debugged and optimized PayPal checkout flow eliminating 15+ critical payment errors and improving transaction success rate to 97.8%.
- Implemented end-to-end PayPal payment solution that accelerated order processing by 40% and enhanced user experience for monthly transactions.
Senior Full-stack Engineer
Embrace IT Technologies
- Led a 5-engineer team to build the ServiceLovers customer rating platform, coding core features while managing development that brought in 13 Danish companies and boosted user engagement.
- Implemented scalable back-end services using Node.js, Express.js, and Nest.js, improving system reliability and reducing response times.
- Optimized API performance by improving endpoint efficiency at both the code and database levels, reducing response times by 70% and enhancing system scalability.
- Strengthened security for a Next.js-based SPA, implementing OAuth, JWT-based authentication, and secure HTTP headers, reducing security vulnerabilities.
- Containerized applications using Docker and orchestrated with Kubernetes, ensuring zero downtime deployments and scalability.
- Optimized the queuing system using RabbitMQ, reducing message processing time by 30% and ensuring smooth task execution.
- Implemented and optimized database migrations, ensuring data integrity and seamless schema updates across production environments.
- Implemented CI/CD pipelines using GitHub Actions, streamlining the deployment process and reducing manual intervention by 70%.
- Collaborated with designers and product managers, ensuring pixel-perfect UI development and an improved 95% user satisfaction rate.
- Converted old JavaScript code to TypeScript, making it easier to update, fixing bugs before they broke the app, and preparing the system to handle growth.
Software Engineer
Saufik
- Developed and optimized an enterprise SaaS project (Projul) for a U.S.-based construction management client.
- Rebuilt old code into reusable building blocks, making the app faster and easier to update.
- Led state management improvements using Redux Toolkit (RTK), reducing unnecessary re-renders and improving efficiency.
- Integrated Web Workers to offload computationally heavy tasks, enhancing application responsiveness and ensuring a smooth user experience.
- Implemented Selenium-based end-to-end testing suite that validates complete user workflows and prevents front-end bugs from reaching production.
Front-end Software Engineer
Ineffable Devs
- Developed and launched the beta version of VanGo, a transport and manpower services startup in the UK.
- Built core functionalities, including order booking, payment processing, and user management for drivers and companies.
- Optimized front-end performance, reducing initial load times by 30% through code splitting and lazy loading and improving Lighthouse scores.
Project History
ServiceLovers: Transforms real-time reviews into business growth opportunities.
Architected the back end with Nest.js, TypeORM, and PostgreSQL to process real-time data, ensuring feedback reached teams in seconds. Deployed on AWS with automated CI/CD via GitHub Actions, achieving 99.9% uptime.
My biggest impact: stabilizing performance under heavy load. Restaurants processing thousands of daily reviews experienced zero downtime, directly boosting client retention and revenue. Integrated AI insights that helped managers spot trends faster and convert unhappy customers.
The result? Employee morale soared with instant recognition, and managers made smarter decisions with real data. One restaurant chain saw 30% revenue growth after switching from sales-based bonuses to our service quality metrics. By focusing on user experience over complex features, I helped create a platform that businesses actually love using and pay premium prices for.
Projul
The math behind the construction was brutal. Estimates with thousands of line items, automatic markups, and change orders that rippled through budgets. My team cracked the code, building calculators that contractors trusted. No more Excel errors costing thousands.
Created Projul's design system from scratch, with every button and workflow optimized for muddy fingers on phone screens. Field workers loved offline functionality. Office managers loved auto-generated invoices.
My proudest achievement? Weekly client demos where contractors' faces lit up seeing paper processes digitized. One saved nearly 15 hours weekly on scheduling alone. By bridging construction sites and offices, we helped small contractors compete like big firms, winning more bids, finishing on time, and getting paid faster.
Asteria.ai
https://www.asteria.ai/en/home/Witnous Smart School
• A learning Management System having 4 Apps (Student, Teacher, School & Witnous Administration).
• Contributed with the Frontend team to develop apps for Students, Teachers, Schools & Witnous administration.
SILC App
Password Hotpot
VanGo
Kamal Tec
Education
Postgraduate Diploma in Cyber Security
Preston University - Islamabad, Pakistan
Bachelor's Degree in Computer Science
University of Engineering and Technology (UET) - Taxila, Pakistan
Certifications
Verified International Academic Qualifications
World Education Services
React + Redux
SoloLearn
Learn Ethical Hacking From Scratch
Zsecurity
Skills
Libraries/APIs
React, Node.js, REST APIs, React Redux, Stripe API, Context API, OpenAI API, API Development, OpenAI Assistants API, Stripe, Zod, Google Maps, NgRx, LinkedIn API, OpenCV, SQLAlchemy, Twilio API, Three.js, WebGL, Facebook API, Plaid API, Vue, Google API, Vue 3, Chart.js, D3.js, Playwright, FFmpeg, TensorFlow, QuickBlox, Puppeteer, Clio API, QuickBooks API, eBay API, Puppet.js, React Query, Claude API, Stripe Connect, Stripe Connect API, Drizzle, AWS Amplify, NetSuite API, Google Maps API, Google Maps SDK, X (formerly Twitter) API, HTML Offline API, Instagram API, React Flow, Web3.js, PyTorch, Entity Framework, jQuery, Open APIs, HubSpot API, Mailchimp API, Salesforce API, OpenGL, React DnD, Django ORM, WebRTC, Mindbody API, MobX
Tools
Postman, Git, GitHub, Slack, Microsoft Teams, Asana, Confluence, ChatGPT, Figma to HTML, Shadcn, Webpack, Figma, AWS IAM, Wix, Nx, Amazon Simple Queue Service (SQS), Firebase Authentication, Adobe Experience Design (XD), SendGrid, MD5, Create React App, JSX, Drizzle ORM, FileMaker Pro, Pytest, Terraform, Bolt CMS, MQTT, Ghost, Zapier, Whisper, Lighthouse, Sentry, TanStack Router, Redux Toolkit, AI Prompts, Google Docs, Make (formerly Integromat), Auth0, Prisma, Claude Code, Shopify Plus, Google Sheets, Amazon CloudWatch, Claude, You Only Look Once (YOLO), Blender, Adobe Photoshop, Expo, Spreadsheets, AWS SDK, NGINX, Google Analytics, GIS, RabbitMQ, Celery, Sequelize, PyCharm, Jira, n8n, Amazon Textract, Microsoft Excel, Haystack
Languages
JavaScript, TypeScript, HTML5, CSS, CSS3, Python, HTML, SQL, TypeScript 4, TypeScript 5, JavaScript 6, TypeScript 3, Bash, PHP, Go, Python 2, Shopify Liquid, TypeScript 2, Java, C#, GLSL, GraphQL, SCSS, Python 3, C++, Rust
Frameworks
Next.js, Express.js, Tailwind CSS, Redux, Material UI, Ant Design, Jest, Selenium, OAuth 2, Angular, Flutter, Flask, Remix, GStreamer, Cypress, JSON Web Tokens (JWT), Payload CMS, Scrapy, Laravel, i18next, TensorFlow Lite, Electron, .NET, ASP.NET, Alpine.js, Starlette, Ruby on Rails (RoR), DSPy, Ember.js, NestJS, React Native, Bootstrap, Django, Django REST Framework, LangGraph, Fastify
Paradigms
Web App Design, App Development, Functional Programming, Responsive Web Design (RWD), Mobile Development, UI Design, Automation, Database Design, Database Development, UX Design, Automated Testing, Manual Testing, Microservices, Hosting, API Architecture, Testing, DevOps, HIPAA Compliance, Marketplace Platforms, Responsive, Gamification, Back-end Architecture, REST, Clean Architecture, Role-based Access Control (RBAC), Rule-based Programming, Fast Healthcare Interoperability Resources (FHIR), HL7 FHIR Standard, DevSecOps, Offline-first Development, Real-time Systems, Agile, Agile Software Development, SCORM, Azure DevOps, Best Practices, Model Context Protocol (MCP), Microservices Architecture, Object-oriented Programming (OOP), Search Engine Optimization (SEO)
Platforms
Visual Studio Code (VS Code), Amazon Web Services (AWS), Vercel, Android, iOS, Heroku, Web, AWS Lambda, Twilio, WordPress, Linux, Kubernetes, Mapbox, Google Cloud Platform (GCP), OpenStack, ConvertKit, Replit, Celigo, Shopify, Azure AI Search, GreenSock Animation Platform (GSAP), Xano, Calendly, Ubuntu, Amazon EC2, Sanity Studio, Blockchain, Ethereum, Mobile, Netlify, GoHighLevel, Windows, HubSpot, LangSmith, Firebase, Docker, Azure, Django CMS, Webflow, FlutterFlow, Harness, Contentful, Apache Kafka
Storage
PostgreSQL, MySQL, MongoDB, JSON, Amazon S3 (AWS S3), Google Cloud, Database Architecture, Cloud Firestore, PostgreSQL 10, Databases, Datadog, Database Administration (DBA), SQL Performance, Data Pipelines, PostGIS, IndexedDB, Redis, Elasticsearch
Industry Expertise
Web Design, Healthcare, Project Management, Marketing, Accounting, Cybersecurity
Other
Software Development, Software Development Lifecycle (SDLC), Development, Storybook, Computer Science, Progressive Web Applications (PWAs), GitHub Actions, Responsive UI, Responsive Web Apps, User Experience (UX), SaaS, Startups, APIs, Artificial Intelligence (AI), Data Scraping, Web Scraping, Product Reviews, ChatGPT API, ChatGPT Prompts, OpenAI, OpenAI GPT-4 API, Payment Gateways, Full-stack, Web Development, Back-end, Minimum Viable Product (MVP), Music Industry, RESTFul APIs, Google, App Design, Apps, Front-end, Cursor AI, CI/CD Pipelines, Website Integration, eCommerce, Mobile App Development, System Architecture, AI Agents, CSV, Large Language Models (LLMs), Agentic AI, LangChain, Full-stack Development, Mobile Apps, Animation, Performance Optimization, Web Security, Cloud Security, Architecture, Generative Artificial Intelligence (GenAI), Performance Testing, API Integration, Data Visualization, Authentication, Software Architecture, Technical Leadership, OAuth, Tesseract, Webhooks, Message Queues, AWS Cloud Architecture, AWS DevOps, Fintech, Airtable, Front-end Development, Back-end Development, Prompt Engineering, WebSockets, Firebase Cloud Functions, Generative Pre-trained Transformer 4 (GPT-4), Data Extraction, Data Collection, User Interface (UI), Websites, Video Editing, User Authentication, Axios, Web Applications, English, Supabase Auth, Debugging, React Three Fiber (R3F), Payment Processing, Healthtech, Digital Resources, Analytics, AI Chatbots, Excel 365, Scripting, Hash, Machine Learning, API Testing, API Design, CTO, POS, Code Review, Quality Assurance (QA), Web App Development, Gemini API, MERN Stack, Documentation, Row-level Security (RLS), Security, AI Integration, Speech-to-Text (STT), Text-to-Speech (TTS), Dashboard Design, Product Design, Headless CMS, AI Tools, Administration, Communication, System Integration, Low Code, Cascading, UTF-8, Clients, Invoice Management, Photo Uploads, PDF, Tables, Two-factor Authentication (2FA), UI Animation, UIP, Invoices, GPS, GPS Integration, Geolocation, Mapbox SDK, Zustand, Content Management Systems (CMS), Google Analytics 4 (GA4), SSL, Education Technology (Edtech), Fractional CTO, Data Transcription, Video Uploading, Videos, Branding, Tracking, Dashboards, Generative Pre-trained Transformers (GPT), Mentorship, Web UI, Online Payments, Augmented Reality (AR), Process Automation, AI Model Training, DALL-E, Single-page Applications (SPAs), Web Crawlers, Cloudflare, Custom Shopify Apps, Shopify Theme, Microsoft Azure, Personally Identifiable Information (PII), Retrieval-augmented Generation (RAG), Radix UI, Vite, Web Content Accessibility Guidelines (WCAG), Monorepos, AI Programming, AI Design, Design, Marketplaces, Payment APIs, BullMQ, FastAPI, Error Handling, Stripe Marketplace, Recommendation Systems, Technical Architecture, Technical Requirements, Vector Databases, Image Analysis, Cloud, Interviewing, Interviews, Azure Blob Storage, Finance, Amazon Route 53, Bug Fixes, Vibe Coding, Workflow Diagrams, Scalability, Generative Design, Touch Design, Push Notifications, RAG Systems, Beta Testing, Screen Recording, Booking, MVP Design, Scheduling, Scheduling Tools, User Roles, Workflow Automation & System Integration, Reporting, NetSuite, AI Architecture, Firebase Hosting, Forecasting, Asynchronous REST APIs, Inventory Management, Intuit QuickBooks, QuickBooks Online, LLM Integration, Multitenancy, Workflows, Cloud Infrastructure, Dashboard Development, Large-scale Web Crawlers, eBay Listings, Crash Reporting, Infrastructure, Infrastructure as Code (IaC), Gemini, Perplexity, Real Estate, Healthcare Software, Internationalization, Mobile-first Design, Service Workers, i18n, Software Engineering, Enterprise SaaS, Senior Users, Azure Database for PostgreSQL, Audio Processing, Computer Vision, Edge AI, Sensor Fusion, Signal Processing, Subscription Processing, Auditing, Indexing, Performance Tuning, Query Optimization, AssemblyAI, Agentic Workflow Design, Integration, Subscriptions, Sports, System Design, Agentic RAG Systems, Product Owner, RAG Architecture, Open Banking APIs, Security Architecture, AI Engineering, Engineering, Collaboration, Amazon Bedrock AgentCore, Model Tuning, Recruitment, Anthropic, Deployment, Amazon RDS, Serverless, Multi-agent Systems, VoIP, Migration, Embeddings from Language Models (ELMo), Stakeholder Management, Non-fungible Tokens (NFT), Smart Contracts, Cloud Networking, Pulumi, Solution Architecture, Telephony, Client Communication, Customer Support, Troubleshooting, DNS, Data Execution, Document Parsing, Natural Language Processing (NLP), Object Detection, Video Analysis, Contract Review, Software as a Service (SaaS), Budgeting, Electronic Payments, Saudi Arabia, Directed Acrylic Graphs (DAG), Consumer Applications, Grocery Delivery, Product Requirements Documentation (PRD), Backups, Data Security, Financial Calculations, Financial Modeling, Web3, Learning Management Systems (LMS), Framer, Robot Operating System (ROS), Robotics, DevOps Engineer, Telegram Bots, Website Performance, IT Consulting, Framer X, Healthcare Services, Insurance Technology (Insurtech), Search Engines, Meetings, Technical Project Management, Shopify Customizations, Shopify Design, Application Security, OWASP, Source Code Review, Web Application Security (Web AppSec), Containers, Data Analytics, Multi-tenant SaaS, Proptech, Third-party APIs, Device Firmware Updates (DFU), MLM Software, Firmware, Open Banking, Booking Systems, Cloud Computing, Scalable Architecture, AI Voice Agents, Answer Engine Optimization (AEO), Google Search Console, Website Optimization, Embedded Systems, Hardware, Data, Authorization, DocuSign, Multi-tenant Architecture, Pgvector, Model Evaluation, A/B Testing, Data Annotation, Text-to-text Transfer Transformer (T5), Mobile Payments, 3D Graphics, 3D Modeling, Computer Graphics, Data Modeling, Digital Twin Development, GL Transmission Format (glTF), Bluetooth, Strapi, System Security Plans, Customer Relationship Management (CRM), Lead Generation, AVFoundation, App Store, HTTP Live Streaming (HLS), Data Structures, TypeORM, Ethical Hacking, Gatsby, Enzyme, Browser Automation, Supabase, Platform as a Service (PaaS), Image Processing, Data Analysis, PayPal, Square, Squarespace, B2B Lead Generation, Google Tag Manager, Algorithms, Cybersecurity Operations, Cybersecurity Automation, Enterprise Cybersecurity, Cyber Defense, Threat Intelligence, AI Development, Bun, RAG Pipelines, Pinecone, AWS Auto Scaling
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