Projects
Things I designed and built end to end, each with something you can try.
Petcare AssistantDemo
2026 · Solo developerAI assistant + CRM on LINE for vet clinics, grooming and boarding shops, running as a public demo. Customers ask, book, pay a deposit and cancel in the chat; the bot answers from the shop's own data and hands over to staff when a decision should not be left to AI.
petcare.rattanun.dev ↗
Next.js · NestJS · PostgreSQL + pgvector · Drizzle · Redis / BullMQ · OpenRouter
Car-rental booking & billing platformWork project
2024 · Siam Orchard GroupThe backend behind a car-rental and tour business in Japan. A booking turns into a quotation, deposit, invoice, payment and receipt on its own, so staff stopped typing documents by hand.
NestJS 11 + Fastify · TypeScript · MongoDB / Mongoose · Zod · INET Payment Gateway · React-PDF