Open to freelance · Hanoi, UTC+7
I'm Nguyễn Mạnh Hùng. I build web and mobile products and ship them to production — currently open to freelance work.
01Work
Two products in production and one open-source tool. Open a case study for the problem and the technical choices.
01Online invitations · Self-service SaaS
A self-service product for online invitations: pick a template, pay once, edit it in the browser and publish a link guests can RSVP from. No yearly fee.
02Mobile app · React Native
An app that records a lecture and shows two-way Korean/Japanese ↔ Vietnamese subtitles in real time, keeps sessions offline-first and syncs them after each lecture.
03Developer tool · Open source
A local-first cockpit for running many coding sessions on one repository, each in its own git worktree, and landing them back without hand-merging.
02Services
Four kinds of work I take on regularly. Don't see what you need? Send a message — I'll give you an honest answer.
SaaS, dashboards and internal tools: frontend, API, database, authentication and an admin panel.
React Native/Expo apps that work offline-first, sync across devices and integrate realtime and AI.
Landing pages, marketing sites and shops: SEO-ready, mobile-first, with payments and order management.
Refactoring, performance and SEO work, custom content editors and monthly maintenance for live sites.
03About
I'm Hùng, a product engineer in Hanoi. I work full-stack: from the database and API to the interface, and then into production.
I'm an Information Technology student at Hanoi Open University, have been building full-stack websites for a few years, and take freelance projects.
I like things that load fast, look beautiful, and still work great five years later. If you want a developer who understands both the code and the user, drop me a message.
Tests live next to the code
900+ test files in mythiep, 500+ in Hadi and 200+ in crossweave; the habit is to write them alongside the feature, not after it.
Decisions are written down before the code
Larger features start from a spec and a plan. mythiep ran a time-boxed spike on the editor and recorded the decision before the schema was fixed.
Secrets never live in the client
Hadi hands the app a 300-second key; mythiep verifies payment notifications with a signature and a secret header on the server.
Accessibility is measured, not eyeballed
Hadi has a WCAG AA contrast test over 56 colour pairs. This site runs axe in its end-to-end tests and scores 100 for accessibility on Lighthouse.
Performance is measured, not guessed
This site scores 99 for performance on mobile Lighthouse with a CLS of 0; the method and the raw numbers are kept in the repo.
Frontend
React · Next.js · TypeScript · Tailwind CSS · Material-UI · Framer Motion · GSAP · Electron
Mobile
React Native · Expo · expo-sqlite
Backend & data
Node.js · Express · PostgreSQL · Prisma · MongoDB · MySQL · Socket.io · Firebase · Auth.js · JWT · Redis · Bun
Infra & tools
Vercel · Supabase · Cloudflare R2 · Git · GitHub · Postman · Figma
04Process
A clear 5-step process. You always know where we are and what's next.
1–2 days
Listen to requirements, define scope, deliverables and a quote. Free of charge.
3–5 days
Wireframes, mockups and a technical plan. You approve before code starts.
Scope-dependent
Code, weekly demos, continuous feedback. I never go dark.
1–2 days
Deploy, domain, SEO basics, admin handover. Ready for customers.
30 days free
Bug fixes and guidance. Optional monthly maintenance after that.
05FAQ
The questions clients ask most before we start.
Landing page: 1–2 weeks. Web app: 1–3 months depending on scope. I'll give you a concrete timeline after Discovery.
Depends on scope. Landing pages start from a few million VND, web apps from tens of millions. Send a message and I'll quote your specific project.
Yes. I work fully remote — calls on Zoom/Google Meet, async over email/Zalo/Slack, whichever you prefer.
The first 30 days of bug fixes are free. After that there's an optional monthly maintenance package if you want me long-term.
By default React + Next.js for the frontend, Node.js for the backend, React Native (Expo) for mobile apps. You don't need to know code — I explain in everyday language.
Yes, as long as it isn't locked into a closed platform (Wix, Squarespace). I audit it for free before quoting.
Usually three milestones: 30% on signing, 40% mid-project (working demo), 30% on handover. Vietnamese bank transfer, or Wise for international clients.
Yes. After full payment the source code is 100% yours, handed over with deployment and editing guides.
06Contact
Available for new projects. Pick the channel that suits you — I reply within 24 hours.