# Tran Manh Tuan > Technical Lead and full-stack engineer. I build, operate and troubleshoot production web systems across application, infrastructure and security layers. Tran Manh Tuan (Trần Mạnh Tuấn) — Technical Lead & Full-stack Engineer: Backend · Cloud Infrastructure · Production Troubleshooting. 10+ years in software engineering, 5+ of them leading teams. Based in Ho Chi Minh City, Vietnam. Available for freelance consulting, backend development, cloud infrastructure and production troubleshooting. Every page of this site exists in English (/en) and Vietnamese (/vi), and each has a Markdown copy at the same URL with `.md` appended. The links below point to the English Markdown copies. ## Profile & contact - [Home](https://tmtuan.dev/en.md): Technical Lead and full-stack engineer. I build, operate and troubleshoot production web systems across application, infrastructure and security layers. - [Resume](https://tmtuan.dev/en/resume.md): Web resume for Tran Manh Tuan — Technical Lead and full-stack engineer working across backend, cloud infrastructure and production operations, with the services he takes on. - [Contact](https://tmtuan.dev/en/contact.md): Available for freelance consulting, backend development, cloud infrastructure and production troubleshooting. Email: tmtuan801@gmail.com. ## Services - [Services](https://tmtuan.dev/en/services.md): What I build and what I do: custom business systems, corporate web platforms, backend and APIs, cloud infrastructure and production troubleshooting. - [Custom Business Systems](https://tmtuan.dev/en/services/business-systems.md): Systems a business runs on every day: cases and sales KPIs, verified memberships and approvals, clinical and home-nursing workflows, campaigns matched to devices. Each project page shows which layers I was responsible for. Examples: Dr.Well-B, TaxPal, Waroku Hospital Karte, Waroku Home-Visit Nursing and a multi-tenant Beacon advertising platform. - [Corporate & Content Web Platforms](https://tmtuan.dev/en/services/web-platforms.md): Corporate, brand and campaign websites that marketing teams update themselves through a CMS, served from a CDN, multilingual where needed, with spam-protected forms and security scanning on every change. Examples: the GO taxi website ecosystem, Wonderia YOKOHAMA, Yokohama Stadium and the IR platform of a listed company. - [Backend Engineering](https://tmtuan.dev/en/services/backend-development.md): Building backends and APIs for business systems and high-traffic platforms, keeping data correct and responses fast through query tuning, caching and background jobs for heavy work. Examples: Dr.Well-B, TaxPal, and a Beacon platform that has handled 761,921 device connections in a single hour. - [Cloud Infrastructure](https://tmtuan.dev/en/services/gcp-cloud-infrastructure.md): Provisioning and managing GCP and AWS infrastructure in Terraform, so every environment can be reviewed and recreated. IAM, secrets, CI/CD and monitoring are in place from day one, which makes each release routine work rather than a risk. - [Production Troubleshooting](https://tmtuan.dev/en/services/production-troubleshooting.md): Finding the real root cause when production breaks and it is unclear whether the application, the cloud or the CDN is at fault, then fixing it and adding the monitoring that keeps it from coming back. Case study: an HTTP 500 that only Googlebot saw. - [Security & Reliability](https://tmtuan.dev/en.md): Investigating security incidents, reviewing infrastructure and access, and hardening production: secrets kept out of source code, and vulnerability and leaked-secret scanning (Trivy, Semgrep, Gitleaks) in CI, so risks are caught before they become incidents. - [Technical Leadership](https://tmtuan.dev/en.md): Keeping a project technically on course: architecture direction and trade-off decisions, reviews that catch risk before release, mentoring, and leading the team through incidents — as Tech Lead on healthcare, tax and accounting, and enterprise web projects. - [Full-stack Web Development](https://tmtuan.dev/en.md): Setting up and maintaining Next.js, React, Nuxt and Vue applications together with the API behind them, and resolving the framework, routing and i18n issues that slow a whole team down — from corporate websites to healthcare systems. ## Engagement - Freelance projects: building a new system, extending one that is already in production, or fixing a production issue. - Working remotely on Vietnam time (UTC+7), with hours that overlap Japan (JST) and Europe, so we can talk during your working day. - Vietnamese or English, with clients in any country. - Every project starts with a detailed look at your requirements, so the scope and price you receive match what you actually need — there is no fixed price list. - Emails are answered as soon as possible. - A good fit: business systems, backends and APIs, GCP and AWS infrastructure, production incidents. - Not the right fit: work that is mainly pixel-perfect UI or heavy animation. - To start: email tmtuan801@gmail.com with the project type, what needs to be built or fixed, the current stack, the timeline and, optionally, a budget range. ## Projects - [Dr.Well-B — Multi-Service Platform for Doctors](https://tmtuan.dev/en/projects/dr-well-b.md): Multi-service platform for doctors and dentists in Japan: verified membership with approvals, profile-targeted ads, dynamic surveys, job search and batch reward points. - [TaxPal — Accounting Brokerage Sales Dashboard](https://tmtuan.dev/en/projects/taxpal.md): Sales analytics for an accounting-services brokerage in Japan: cases, KPI targets against actuals, rankings and pipeline conversion by staff member, team and company. - [Waroku Hospital Karte — Cloud EMR for Hospitals](https://tmtuan.dev/en/projects/waroku-hospital-karte.md): A cloud medical record and clinical workflow platform for psychiatric hospitals in Japan: patient charts, multi-step clinical orders, wards, beds, nursing and schedules. - [Waroku Home-Visit Nursing — Cloud Care Platform](https://tmtuan.dev/en/projects/waroku-home-visit-nursing.md): A cloud platform for home-visit nursing in Japan: patients and their homes, case records and handover, nursing orders and plans, visit schedules, reports and assessments. - [GO Inc — Multi-site Platform on GCP & AWS](https://tmtuan.dev/en/projects/go-inc.md): An ecosystem of 4 websites for the GO taxi brand — a 5-language product site, ATS-connected recruiting, a support center and corporate IR, with Slack-moderated publishing on Google Cloud + AWS. - [Wonderia — Multilingual Site on Google Cloud](https://tmtuan.dev/en/projects/wonderia.md): The multilingual brand website of Wonderia YOKOHAMA (wonderia.jp) — 4 languages, marketing self-publishing via Contentful, running serverless on Google Cloud. - [Yokohama Stadium — Official Site & Live Feed](https://tmtuan.dev/en/projects/yokohama-stadium.md): The official website of Yokohama Stadium (Hamasta) with a live play-by-play system — static-first on a CDN, event-driven serverless pipeline on Google Cloud and AWS. - [Corporate IR Platform — Custom CMS on GCP](https://tmtuan.dev/en/projects/corporate-ir-platform.md): A corporate and IR website platform for a listed Japanese company — a fully self-built CMS, a Firestore-to-BigQuery data pipeline, and Google Cloud infrastructure behind a WAF. - [Fullswing — Nuxt Content Site & CDN Images](https://tmtuan.dev/en/projects/fullswing.md): Fullswing, an article-based content site on a modern Nuxt stack in a Turborepo monorepo — Contentful images served through Akamai CDN with automatic cache purging on every publish. - [AI Brand Site — WebGL, Contentful & ChatOps](https://tmtuan.dev/en/projects/ai-brand-site.md): The AI brand website of a Japanese technology group — WebGL visuals, 15 Contentful content types, Slack-based content approval, and modernisation of a system running for years. - [AI Link — Static Next.js Corporate Site](https://tmtuan.dev/en/projects/ai-link.md): AI Link's bilingual Japanese–English corporate website for B2B AI services — Next.js fully static on a CDN, a contact form with layered spam protection, and near-zero operating cost. - [BALLPARK Xmas — Campaign Site & Instagram API](https://tmtuan.dev/en/projects/ballpark-xmas.md): The BALLPARK Xmas YOKOHAMA KANNAI campaign site — Instagram integration with a fully automated token lifecycle, and Contentful content rendered per request instead of rebuilding the site. - [Beacon Content Platform — BLE Ad Backend & API](https://tmtuan.dev/en/projects/beacon-content-platform.md): A multi-tenant BLE/iBeacon advertising platform that recorded 761,921 device connections in a single hour while matching campaigns and delivering context-aware content. ## Articles - [How Discord indexes trillions of messages](https://tmtuan.dev/en/articles/discord-trillions-message-indexing.md): Discord replaced its Redis queue, split Elasticsearch into small cells and routed bulk writes by destination to operate search at trillion-message scale. - [Why an async payment platform still needs a strongly consistent ledger](https://tmtuan.dev/en/articles/uber-gulfstream-payments-ledger.md): Uber Gulfstream combines an asynchronous payment pipeline with immutable money orders, zero-sum validation and strongly consistent ledger balances. - [How Shopify handled 1.27 million requests per second during Black Friday](https://tmtuan.dev/en/articles/shopify-bfcm-risk-mitigation.md): System-design lessons from BFCM 2022: distribute load, protect the database, cache repeated reads and prepare for traffic spikes. - [Partition Relational Databases Before You Move Data](https://tmtuan.dev/en/articles/partitioning-relational-databases-at-scale.md): Lessons from GitHub's MySQL partitioning: schema domains, boundary linters, consistency checks, cutover mechanics, and production rollout. - [What Shopify's MySQL Inventory Reservation Migration Teaches](https://tmtuan.dev/en/articles/scaling-inventory-reservations.md): Lessons from Shopify's Redis-to-MySQL migration: bounded row pools, lock design, connection visibility, and a safer rollout strategy. - [Docs-as-code Knowledge Base + Context Graph for a 15-project portfolio](https://tmtuan.dev/en/articles/knowledge-base-docs-as-code-context-graph.md): Docs for 15 projects had drifted from the code. A docs-as-code KB, a context graph and an MCP server for AI agents, measured in 126 blind-graded sessions. - [How I Traced a Googlebot-only HTTP 500 Across Next.js, Cloud Run and the Hosting Edge](https://tmtuan.dev/en/articles/googlebot-500-firebase-hosting-nextjs.md): Users and every other crawler got 200 while Googlebot got 500 site-wide. The cause: a 404-path regression amplified by crawler verification at the hosting edge. ## External profiles - [LinkedIn](https://www.linkedin.com/in/tmtuan801/) - [GitHub](https://github.com/tu801) ## Optional - [All projects](https://tmtuan.dev/en/projects.md): Selected engineering work — backend services, cloud infrastructure and web applications. - [All articles](https://tmtuan.dev/en/articles.md): Production write-ups and reference implementations: what broke, how it was narrowed down, what the cause turned out to be, and what was put in place afterwards. - [Privacy](https://tmtuan.dev/en/privacy.md): What this site measures with Google Analytics, only after you accept, what your browser stores, and how to change your choice. - [CV (PDF)](https://tmtuan.dev/resume/tran-manh-tuan-resume.en.pdf): The résumé as a two-page PDF. - [Vietnamese version](https://tmtuan.dev/vi.md): Every page is also written in Vietnamese, under /vi/.