I'm Andrei Tan, A Senior Full Stack Engineer with 12+ years of experience building and scaling multi-tenant SaaS platforms, payment systems, and customer-facing web applications. I specialize in React, Next.js, TypeScript, PostgreSQL, Stripe integrations, API architecture, and secure cloud-native systems. I’ve led end-to-end product delivery, implemented tenant isolation, and improved platform reliability to support complex business workflows. I enjoy modernizing legacy codebases while upholding security, performance, and maintainability, and I thrive when collaborating with product and engineering teams to deliver scalable, production-ready features.

Andrei Tan

I'm Andrei Tan, A Senior Full Stack Engineer with 12+ years of experience building and scaling multi-tenant SaaS platforms, payment systems, and customer-facing web applications. I specialize in React, Next.js, TypeScript, PostgreSQL, Stripe integrations, API architecture, and secure cloud-native systems. I’ve led end-to-end product delivery, implemented tenant isolation, and improved platform reliability to support complex business workflows. I enjoy modernizing legacy codebases while upholding security, performance, and maintainability, and I thrive when collaborating with product and engineering teams to deliver scalable, production-ready features.

Available to hire

I’m Andrei Tan,
A Senior Full Stack Engineer with 12+ years of experience building and scaling multi-tenant SaaS platforms, payment systems, and customer-facing web applications. I specialize in React, Next.js, TypeScript, PostgreSQL, Stripe integrations, API architecture, and secure cloud-native systems.

I’ve led end-to-end product delivery, implemented tenant isolation, and improved platform reliability to support complex business workflows. I enjoy modernizing legacy codebases while upholding security, performance, and maintainability, and I thrive when collaborating with product and engineering teams to deliver scalable, production-ready features.

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Experience Level

Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Expert
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Language

English
Fluent

Work Experience

Senior Full Stack Engineer at Cognizant Romania
April 1, 2023 - Present
Led end-to-end full-stack development for distributed fintech and enterprise platforms using React, TypeScript, Next.js, Redux, and Node.js. Designed and consumed RESTful APIs and GraphQL, implemented microservices, and deployed on Docker with AWS. Drove architecture decisions to improve scalability and reliability, reduced latency via caching, and ensured maintainable codebases through code reviews and standards enforcement. Collaborated with product owners and stakeholders to translate business requirements into scalable technical solutions, delivering high-quality features with strong performance and security.
Senior Full Stack Engineer at Stripe
January 1, 2020 - March 31, 2023
Delivered production-grade features for Stripe's distributed systems, focusing on frontend (React, TypeScript) and backend services (Node.js). Implemented RESTful APIs, GraphQL, and microservices with Docker and CI/CD pipelines (GitHub Actions, Vercel). Led performance optimizations and ensured security/compliance in payments workflows. Collaborated with cross-functional teams to refine requirements and ship reliable features for global users.
Full Stack Engineer at Carousell
October 1, 2015 - December 31, 2019
Built full-stack features for Carousell's platform (Singapore / Hybrid), leveraging React, TypeScript, Next.js, and Node.js. Implemented customer-facing UI and robust backend services, including RESTful APIs and GraphQL, with Redis caching and PostgreSQL. Drove system scalability improvements, mentored juniors, and collaborated with product teams to deliver high-impact features in a fast-paced environment.
Junior Full Stack Developer at NCS Group
July 1, 2013 - September 30, 2015
Developed backend services and REST APIs for enterprise systems, supported frontend interfaces, and debugged production issues to improve stability. Collaborated with senior engineers to refine architecture and development practices, contributing to overall system reliability and internal workflow enhancements.
Senior Full Stack Engineer at Carousell
October 1, 2015 - December 1, 2019
Collaborated with cross-functional teams to deliver production-ready features for a fast-moving marketplace. Improved system observability with structured logging and monitoring. Developed full-stack applications in Node.js and React supporting millions of users. Built real-time messaging and chat with WebSockets, designed scalable APIs and backend services for marketplace features. Enhanced frontend performance and UX, and designed notification/messaging systems integrated with backend services. Improved user engagement through real-time features.
Junior Full Stack Developer at NCS Group Singapore
July 1, 2013 - September 1, 2015
Collaborated with cross-functional teams to deliver production-ready features in fast-paced environments. Improved system observability and debuggability through structured logging and monitoring. Developed full-stack applications using Node.js and React, supporting millions of users. Built messaging and chat systems with real-time updates via Web Sockets. Implemented scalable APIs and backend services for marketplace features; enhanced frontend performance and UX; created notification and messaging systems; improved user engagement with real-time features.
Senior Full Stack Developer at Cognizant Romania
April 1, 2023 - Present
Led full-stack development initiatives, delivering scalable frontend dashboards and backend services. Implemented React/TypeScript-based UI and Python/Node.js-based services, deployed on AWS with Docker/Kubernetes. Collaborated with remote cross-functional teams, contributed to system architecture, QA processes, and agile delivery, and drove performance optimizations and maintainability improvements across applications.
Senior Full Stack Engineer (Contract) at Stripe
January 1, 2020 - March 1, 2023
Developed scalable frontend features for payments and operational dashboards using React, TypeScript, Next.js, Redux, Zustand, HTML5, CSS3, and Tailwind. Built backend services with Python and Node.js (Express), integrated REST APIs and GraphQL, and leveraged AWS, Docker, CI/CD, and Kubernetes. Led frontend state management improvements, contributed to system architecture decisions for cloud-native deployments, and mentored junior developers to improve code quality and delivery velocity.
Senior Full Stack Engineer at Stripe Remote / Global
January 1, 2020 - March 31, 2023
Built payment processing systems supporting authorization, capture, settlement, and subscription billing flows across global merchant platforms. Designed event-driven transaction services using Node.js, TypeScript, PostgreSQL, and Kafka, improving consistency across distributed payment systems. Developed merchant onboarding and payment-account integrations aligned with Stripe Connect principles, supporting scalable marketplace-style payment flows. Implemented reconciliation platforms that improved financial data accuracy and reduced transaction investigation effort. Optimized payment APIs and backend services, increasing throughput and improving platform reliability under high transaction volumes. Partnered with product and engineering teams to deliver secure, production-ready financial features while maintaining strict compliance standards. Contributed to architecture reviews, testing standards, and code quality initiatives that reduced production incidents.
Senior Full Stack Engineer at Carousell Singapore
October 1, 2015 - December 31, 2019
Built marketplace services supporting listings, messaging, profiles, and transaction workflows for high-volume buyer-seller interactions. Designed scalable REST APIs using Node.js and PostgreSQL, improving search performance and application responsiveness. Implemented Redis caching and database optimization strategies that reduced infrastructure load and improved user experience. Developed React-based customer-facing features that increased engagement and streamlined listing management workflows. Delivered secure account management and authentication capabilities supporting millions of marketplace interactions. Collaborated closely with product stakeholders to launch new revenue-generating platform capabilities.

Education

Master’s Degree in Computer Science at National University of Singapore
August 1, 2009 - May 1, 2013
Master's Degree in Computer Science at National University of Singapore
August 1, 2009 - May 1, 2013
Master’s Degree in Computer Science at National University of Singapore
August 1, 2009 - May 1, 2013
Master's Degree in Computer Science at National University of Singapore
August 1, 2009 - May 1, 2013
Master’s Degree in Computer Science at National University of Singapore
August 1, 2009 - May 1, 2013

Qualifications

Master's Degree in Computer Science
August 1, 2009 - May 1, 2013

Industry Experience

Financial Services, Software & Internet, Professional Services, Retail, Education, Media & Entertainment