Looks like you have JavaScript disabled. For the full Twine experience, you will need to re-enable it.

Hi, I’m Kai Lee, a full-stack software engineer with 8+ years of experience building scalable web applications, payment systems, and data-driven platforms. I specialize in SPA architectures with React and TypeScript, integrating external APIs, and delivering end-to-end product development—from frontend interfaces to backend services and deployment. I’m comfortable working independently in fast-moving product teams and supporting international platforms with multilingual user interfaces. I’ve designed analytics dashboards, built high-performance transactional workflows, and created API-driven systems. I’m passionate about performance, reliability, and secure, scalable systems, and I enjoy collaborating with cross-functional teams to ship impactful features.…Hi, I’m Kai Lee, a full-stack software engineer with 8+ years of experience building scalable web applications, payment systems, and data-driven platforms. I specialize in SPA architectures with React and TypeScript, integrating external APIs, and delivering end-to-end product development—from frontend interfaces to backend services and deployment. I’m comfortable working independently in fast-moving product teams and supporting international platforms with multilingual user interfaces. I’ve designed analytics dashboards, built high-performance transactional workflows, and created API-driven systems. I’m passionate about performance, reliability, and secure, scalable systems, and I enjoy collaborating with cross-functional teams to ship impactful features.

Kai Lee

Web Developer, Full Stack Developer, Front-End Developer, +4

5.0 (1 review)

Hi, I’m Kai Lee, a full-stack software engineer with 8+ years of experience building scalable web applications, payment systems, and data-driven platforms. I specialize in SPA architectures with React and TypeScript, integrating external APIs, and delivering end-to-end product development—from frontend interfaces to backend services and deployment. I’m comfortable working independently in fast-moving product teams and supporting international platforms with multilingual user interfaces. I’ve designed analytics dashboards, built high-performance transactional workflows, and created API-driven systems. I’m passionate about performance, reliability, and secure, scalable systems, and I enjoy collaborating with cross-functional teams to ship impactful features.…Hi, I’m Kai Lee, a full-stack software engineer with 8+ years of experience building scalable web applications, payment systems, and data-driven platforms. I specialize in SPA architectures with React and TypeScript, integrating external APIs, and delivering end-to-end product development—from frontend interfaces to backend services and deployment. I’m comfortable working independently in fast-moving product teams and supporting international platforms with multilingual user interfaces. I’ve designed analytics dashboards, built high-performance transactional workflows, and created API-driven systems. I’m passionate about performance, reliability, and secure, scalable systems, and I enjoy collaborating with cross-functional teams to ship impactful features.

Available to hire

Hi, I’m Kai Lee, a full-stack software engineer with 8+ years of experience building scalable web applications, payment systems, and data-driven platforms. I specialize in SPA architectures with React and TypeScript, integrating external APIs, and delivering end-to-end product development—from frontend interfaces to backend services and deployment.

I’m comfortable working independently in fast-moving product teams and supporting international platforms with multilingual user interfaces. I’ve designed analytics dashboards, built high-performance transactional workflows, and created API-driven systems. I’m passionate about performance, reliability, and secure, scalable systems, and I enjoy collaborating with cross-functional teams to ship impactful features.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Software Developer at TomeBlock

December 1, 2022 - Present

Designed and implemented end-to-end features across React frontend and Node.js backend services for high-volume e-commerce and payment platforms. Developed SPA interfaces and reusable UI components supporting complex user workflows and transactional states. Built and integrated REST APIs for onboarding, checkout flows, and payment lifecycle management. Implemented analytics dashboards and data visualizations for operational monitoring and reporting. Optimized application performance through improved rendering patterns, API request management, and database query optimization. Contributed to deployment and infrastructure improvements using Docker and CI/CD pipelines. Participated in maintaining production environments and resolving incidents affecting frontend and API services. Improved automated testing coverage across frontend and backend systems. Worked closely with product teams to deliver secure, scalable user-facing financial systems.

Software Engineer at Klarna

June 1, 2020 - August 1, 2022

Developed React-based frontend components supporting global payment workflows. Built UI systems that accurately represented asynchronous backend state transitions in distributed financial systems. Improved customer-facing payment flows by enhancing clarity, state handling, and error recovery UX. Collaborated with cross-functional teams (design, product, backend) to ship incremental UI improvements. Standardized frontend error handling patterns across payment microservices. Optimized frontend performance for high-traffic financial transaction interfaces. Contributed to integration and end-to-end test suites validating critical payment paths. Mentored junior engineers in frontend architecture and testing strategies. Improved documentation for frontend workflows and component usage patterns. Supported incident investigations affecting frontend behavior in production.

Junior Software Developer at Samsara

May 1, 2018 - March 1, 2020

Developed web interfaces integrated with backend APIs for healthcare and enterprise systems handling sensitive data. Built reusable UI components for data-heavy applications. Supported frontend bug resolution and production defect analysis. Assisted in implementing early UI testing frameworks. Collaborated with QA and product teams to validate business-critical workflows.