Mannam Market — An AI-run marketplace for Koreans in Vietnam

Overview

Mannam Market is an AI-driven secondhand marketplace and community platform for the Korean community in Ho Chi Minh City. It was designed to fix what group-chat trading on KakaoTalk cannot do: spot bad actors, keep information in one place, and make anything searchable.

The core idea is an almost unattended operation — 97% handled by AI, one hour of operator time a day. A single photo is enough to list an item, and a scammer database plus a trust score keep transactions safe. It is a live mobile service.

Key features

AI automation

• AI listing: take a photo and Claude Vision writes the title, description and category
• Live Korean ↔ Vietnamese chat translation: Google Cloud Translation removes the language barrier from negotiation
• AI support chatbot: handles repeat questions so operators don't have to

Trust and safety

• Scammer database: the killer feature — search reported fraud history
• "Mannam temperature" trust score: computed automatically from trade count, reviews and reports
• Three-strike auto-ban: a rules engine detects abnormal patterns and applies sanctions

Community and business

• Business directory: listings for Korean-run businesses with a tiered partner advertising model
• Live chat and notifications: transaction state synced over Socket.io
• Korean-community news feed: local news collected, translated and summarised automatically

Tech stack

Mobile app (cross-platform)

Expo (React Native) — iOS / Android / Web from one codebase
TanStack Query + Zustand — state management
Socket.io-client — realtime communication
MapLibre — maps for meetup locations
i18next — Korean / Vietnamese

Backend

Node.js + Express + TypeScript
Prisma ORM + PostgreSQL 16
JWT authentication + Bcrypt
Redis (sessions / rate limiting)
Socket.io — realtime chat and notifications

AI and infrastructure

Claude API — Vision listing analysis, support chatbot
Google Gemini / Cloud Translation — news and chat translation
Firebase Cloud Messaging — push notifications
AWS S3 + Cloudflare R2 — image storage
Turbo + pnpm monorepo / GitHub Actions CI/CD

Scale

• 61 database tables (Prisma schema)
• 50+ REST API endpoints
• 85 mobile screens (Expo Router)
• Five separate domains: landing, app, admin, API and CDN
• Two languages: Korean and Vietnamese

Architecture notes

A monorepo splits the landing page (Next.js), mobile app (Expo), admin dashboard (Next.js), API server (Express) and CDN. The admin dashboard is designed so an operator can handle live statistics, report moderation and listing approvals in under an hour a day — the goal being a service that stays sustainable with a very small team.