I’m Lei Sun. I currently focus on AI engineering, platform engineering, developer tooling, and fintech validation work.
During my nearly two years at PayPal, I concentrated on turning complex payment migration and validation work into reproducible, verifiable, and handoff-ready engineering systems: standardized local environments, Docker / Makefile workflows, Playwright E2E tests, API behavior evidence, execution evidence, and failure retrospectives.
My open-source projects revolve around Agent Workflow, Tool Calling, MCP code context, RAG applications, Function Calling tool registries, full-stack scaffolding, and frontend component platforms.
Before PayPal, I worked on the front-end integration of Disney Resort’s AI digital-human customer service system, and for a long time led Trip.com’s international site content platform, covering React, Next.js, Node.js SSR, SEO, multilingual content, mobile experience, and front-end engineering evolution.