I'm Dang H., co-founder of Cóc Trọ and a full-stack developer in Hanoi. I design and build websites and mobile apps, from the first screen to the deployed server.
Concept sites I designed and coded from scratch between 2023 and 2026, each tested on phones from 320 px up to wide desktop. Open a project for the full case study.
I care about the details people notice without knowing why: type that fits the screen, buttons that feel right under a thumb, and pages that never scroll sideways.
Every project is checked at these widths before it ships, on real phone profiles, not only a resized desktop window. The frames below are drawn to scale.
Design, front-end, back-end and deployment. One person from the first screen to the live server.
Responsive sites and web apps in React, Next.js, Vue or Angular that look right on every phone, like the concept sites above, plus WordPress and Shopify when that is what a business already runs on. Landing pages, online stores, dashboards and admin panels.
Cross-platform apps in React Native, Expo or Flutter, and native apps in Swift for iOS and Kotlin or Java for Android, with maps, gestures and real booking flows. I also fix bugs and add features to apps that already exist.
REST and GraphQL APIs in NestJS, Node.js, Java Spring Boot or Python, backed by PostgreSQL, MySQL, MongoDB or Firebase, with sign-in, payments, admin tools and review workflows built in.
Apps started with AI tools like Lovable, Bolt or Cursor, or left half-done by another developer: I read the code, fix what is broken and ship it to a Linux VPS, AWS, Google Cloud or Vercel with Docker, CI/CD and HTTPS, including App Store and Google Play releases.
YouTube videos, Shorts, Reels and TikToks, podcasts and ads, cut with clear pacing, captions and motion graphics. The edits are on cocfolio.com/video.
Word-by-word captions, list graphics, logo pop-ins and highlights, for videos that people watch with the sound off.
I ask questions before I start, so the scope is clear for both of us.
A first version of the key screens to react to, then revisions.
Written updates every working day and a live link to try on your own phone.
Tested work, a clean Git repository and a short README.
Leave your details and I'll get back to you, usually within a few hours. Or message me directly on Telegram.