01 / 04
Test-first thinking
Four years in QA taught me to write the failing case before the feature. Even when I'm not writing the test file, I'm sketching the edge cases in my head — zero, scale, the network blinks.
{ story }
Nine years, four turns in the road.
I didn't start in a bootcamp. I started in a QA chair, watching real builds break under real load. These are the four moments that bent the trajectory.
- 2016 — 2020
- FPT Software, HCM
- tester → developer
“The bug I missed was the one that taught me to read code like an attacker.”
My first job out of Cần Thơ wasn't building anything — it was breaking things on purpose. I joined FPT Software as a manual tester on enterprise .NET projects, and for the first two years my job was to find what the developers couldn't see. I wrote hundreds of test cases, ran them by hand, then watched the same bugs slip into production anyway because we caught them too late in the cycle.
So I started writing the test plans earlier. Then I started writing the automation. By the end of that stretch the team had cut production issues by about 30%, and I'd quietly crossed over into the dev side of the room. I learned that quality isn't a phase at the end of a project — it's a way of reading every line you write.
I still open a new file the way a tester opens a feature: looking for the seam where it will fail.
- 2020 — 2023
- frontend engineer
- payment & real-time products
“Frontend is where the engineering finally meets a human.”
The move to frontend started with a payment processing web app — Next.js, Gatsby, third-party APIs that had opinions about how money should move. The UI looked simple. The states behind it did not. A single failed webhook could leave a user staring at a spinner while their card was already charged, and there was nowhere to hide.
From there I joined a real-time push notification product where the UI had to keep up with thousands of events scrolling through Ag-Grid without dropping frames. I learned that performance is a feature and that "just rerender it" is the most expensive sentence in frontend. I started caring about render budgets the way I used to care about test coverage.
Frontend stopped being "the CSS part" for me the day a 200ms jank cost someone a transaction.
- 2023 — 2025
- fullstack engineer
- talent platform · 100+ companies
“Owning the full stack means owning the full failure mode.”
For two and a half years I worked on a talent acquisition platform trusted by more than a hundred global companies. The frontend was React and Next.js with Tailwind and shadcn; the backend was Node and Express, deployed in Docker against Postgres. I built the CV→PDF export, the PDF parser that pulls structured data back out, the Nodemailer pipeline that had to never send the wrong email to the wrong person, and the OAuth/SSO flows that keep enterprise tenants quietly separated.
Backend ownership changed how I think about features. A button I shipped on Tuesday became a queue job I was debugging on Thursday and a Postgres index I was adding on Friday.
The full stack isn't a resume line. It's the pager that goes off when any layer breaks.
- 2025 — now
- Penguin Secret Agency
- autonomous commerce · psa.team
“The hardest part of agentic systems is the part where the agent is wrong.”
In May 2025 I joined Penguin Secret Agency as a fullstack engineer. We're building autonomous commerce systems — ShopQuantum.AI, a storefront that operates without a human in the loop, and FangBot.AI, a virtual business with 59+ AI employees running sales, marketing, support, and ops.
My day-to-day is React/Next on the surfaces humans touch, and Python + Node on the runtime the agents live in. The new muscle I'm building: designing the seams where deterministic code hands control to a probabilistic agent — and the override paths a human takes back when the agent gets it wrong.
After nine years debugging code I wrote, I'm learning to debug decisions a model made.