2021 — present
Estuary Solutions — Software Engineer, now Tech Lead
Backend lead on each of the projects below.
- Vietnamese-language AI assistants — two now live in production, sole engineer on the core AI runtime and the backend behind them. The larger one answers from the company’s own documents through RAG over a vector store and acts on live systems through roughly a hundred tools served over MCP; the second is retrieval-only. Intent classification routes each turn and narrows the tool set offered to the model, since describing the whole catalogue costs more than twice its context window; a sixty-case end-to-end regression suite gates every change
- Both run on models hosted in-house rather than a vendor API — I chose and deployed the language model, the embedding model and the reranker, and tuned the serving stack around them
- In-app messaging and social features — real-time delivery over SignalR, scaled across instances with a Redis backplane; messaging, media and the social graph each kept in their own store behind one service
- Event ticketing and on-site check-in — registration, ticket issue and check-in at the gate, built into the member app. The largest event it has carried sold more than twelve thousand tickets
- Member engagement and loyalty platforms — services split by responsibility, with a dozen background workers behind them
- Product traceability — unique-identifier and QR generation, industrial label printing, warehouse scanning tools, and the lookup that takes a single code and returns where that item came from and everywhere it has been since
- Virtual running events — one multi-country app serving participants across several Southeast Asian markets
ASP.NET Core, Entity Framework Core, PostgreSQL, SQL Server, Kafka, Docker, Python for the AI work