Yio Chou
Product-minded backend engineer with 7+ years turning fuzzy requirements into production systems. Built usage-based billing at NT$5M+/month and a rule engine insurers change without a release. Seeking senior backend roles on AI product teams.
Work Experience
Crescendo Lab, Senior Software Engineer 2025/07 - Present
Tech: Python, FastAPI, React, PostgreSQL, Cloud Run, BigQuery, dbt, Terraform, Pub/Sub
- Built the usage-based credits billing system from GTM/Finance requirements to production, cutting top-up from ~5 days to 3 minutes. It processes NT$5M+/month across 13 paid features, with automated revenue recognition.
- Rebuilt billing as a shared platform. Any new paid feature can plug in and start charging within a day.
- Automated product provisioning from HubSpot orders, a setup step CSMs previously configured by hand.
OneDegree, Senior Backend Engineer 2021/10 - 2025/04
Tech: Python, PostgreSQL, SQLAlchemy, GitLab CI
- Led a team of 4 backend engineers; owned sprint planning and mentored the team on system design and career growth.
- Built a rule engine that runs insurer-written Python in a sandbox. Underwriting and pricing changes ship without an engineering release.
- Refactored core insurance modules around business domains, clarifying undocumented logic with PMs before each change.
- Built deployment tooling and status dashboards that the whole engineering team used daily.
SoundOn, Backend Engineer 2020/07 - 2021/07
Tech: Node.js, PostgreSQL, GCP, Kubernetes, BigQuery, Dataflow, CircleCI, Firebase, React, Redux
- Migrated the platform database from Firestore to PostgreSQL with zero downtime, normalizing inconsistent documents during the cutover.
- Built hourly ETL pipelines on BigQuery and Dataflow, aggregating listening stats to power the creator analytics dashboard and podcast leaderboard.
- Ran backend services on GKE and tuned PostgreSQL queries and indexes for high-traffic podcast analytics.
LJIT.io, Frontend/Backend Engineer 2018/05 - 2020/02
Tech: Node.js, Express.js, MongoDB, MySQL, Redis, AWS S3, React/Redux, Webpack, Docker
- Built smart contracts, React/web3 frontends, and backend services across blockchain, streaming, and gaming client projects.
- Ran the team’s study group, presenting on SOLID, database isolation levels, and React state management.
Education
National Central University 2013/09 - 2017/07
Bachelor of Computer Science
Skills
- Languages: Python, TypeScript/JavaScript
- Backend: FastAPI, Node.js/Express, SQLAlchemy, REST APIs, event-driven services, BullMQ
- Data & Storage: PostgreSQL, MySQL, MongoDB, Redis, BigQuery, dbt, Dataflow
- Infrastructure: GCP (GKE, Cloud Run, Pub/Sub), Kubernetes, Docker, Terraform, CircleCI, GitLab CI
- Frontend: React, Redux
- Tooling: Claude Code