Redesigned the async integration that handles bulk business-card distribution. Replaced an in-progress design with a Pub/Sub × Cloud Tasks BufferTask hybrid that separates fan-out from execution-side rate control, removing dead-letter failures caused by upstream API rate limits and the manual recovery work that used to follow them.

Built API and RPA integrations connecting major e-commerce platforms (Amazon, Rakuten, Shopify, ZOZO, Next Engine) to a SaaS that consolidates inventory and sales data for retailers. Worked across the stack — from an async batch pipeline on AWS Lambda + Celery + Redis, to AI-assisted development infrastructure, to improvements to the GitHub Actions CI.

Drove PoC projects end-to-end as the engineering lead of a 3-person team, while also contributing as an engineer to enterprise projects. In a joint project with a railway company, built a generative-AI–driven recommendation product that delivered a new experience for restaurant and tourism discovery; on the enterprise side, built RAG-based document search for a corporate chatbot.