John Doan
Software Engineer — Java Backend • Python • AI/RAG
Associate-level engineer focused on practical, production-style backend systems and data workflows with clear run steps, tests, and reviewable artifacts.
Remote / Open to relocate
john@johnvdoan.com
Concise resume designed for quick review. Full professional resume available upon request.
Summary
- Build backend services and APIs in Java and Python with clear contracts, validation, and documented endpoints (OpenAPI/Swagger).
- Deliver data workflows and ETL with SQL and reproducible artifacts; comfortable with SQLite/DuckDB for local marts and rapid iteration.
- Project work in AI/RAG: retrieval + grounding patterns and run logging to keep outputs debuggable.
- Production-minded habits: automated testing (JUnit/pytest), structured logging, Docker packaging, and CI-style checklists.
Experience
Independent Developer — Self-Directed Projects
January 2023 – Present
- Built backend and data projects across Java and Python: API services, ETL pipelines, and analytics deliverables with reviewable outputs.
- Packaged FastAPI scoring endpoints with tests, structured logging, Docker, and CI-style checks; wrote short runbooks (
how to run+what to review). - Implemented Java desktop and backend patterns (service/repository layers, SQLite via JDBC, Maven builds, and JUnit basics).
- Produced concise evaluation notes for ML work (threshold trade-offs, confusion matrix, lift/decile summaries) and documented assumptions/limitations.
Selected Projects
Java Job Application Tracker (Stages 1–5)
Java • Maven • Swing UI • SQLite/JDBC • Search/Sort • JUnit basics • Packaging
- Staged build from console CRUD to desktop UI with SQLite persistence; added search/sort and basic tests.
Customer Metrics Pipeline & API
Python • FastAPI • ETL • Artifacts • OpenAPI
- Built an ETL pipeline producing curated artifacts and exposed scoring via a FastAPI endpoint with Swagger/OpenAPI docs.
RAG Mini Chat (Stages 1–3)
Retrieval • Grounding • Run logging
- Implemented staged retrieval workflows and run logs to make responses traceable and debuggable.
Support Ticket Analytics
DuckDB • ETL • Ops KPIs • Text analysis
- Created a small DuckDB-based mart and analyzed ticket text to surface recurring operational themes and trends.
Embedded Resume PDF
Skills
Java Backend
Java 17+
Maven
JUnit 5
JDBC
SQLite
Service/Repository layers
Python Backend / API
Python
FastAPI
Pydantic
REST APIs
OpenAPI/Swagger
Data
SQL
ETL
DuckDB
SQLite
Pandas
AI / ML (project work)
RAG basics
Embeddings (concepts)
Evaluation/logging
Classification baselines
Delivery
Docker
CI checklists
Git/GitHub
Clear documentation
Root-cause analysis
Cross-team coordination