NetLink

Built a complete chat platform from scratch, a Go backend, a Next.js + Bun web client, and a React Native mobile app, all sharing a single bidirectional WebSocket protocol.
Designed a concurrent WebSocket server using Go's goroutines and channels to handle thousands of simultaneous connections with low-latency message fan-out.
Architected a lightweight, framework-free messaging protocol with persistent PostgreSQL storage for chat history, presence, and delivery state.
Implemented the React Native mobile client with shared state management and offline-resilient message queuing, mirroring the web client feature set.

A real-time chat application with web and mobile clients.

Tech Stack

Backend: Go (stdlib net/http), PostgreSQL (pgx), Gorilla WebSocket
Frontend: Next.js 16, React 19, Tailwind CSS v4, TypeScript
Mobile: Expo SDK 54, React Native, Zustand, TypeScript
Deployment: Docker (Railway), Vercel (frontend), EAS Build (mobile)

Features

Real-time messaging via WebSocket (multi-device support)
Direct and group conversations
Message editing, deletion (soft delete), forwarding
Emoji reactions (system + custom)
Voice messages with waveform visualization
Email verification and password reset (SMTP)
Session-based authentication (cookie + bearer token)
Optimistic UI updates on web and mobile
Rate limiting on auth endpoints

Prerequisites

Go 1.25+
PostgreSQL
Node.js / Bun (for frontend)
Expo CLI (for mobile)

Deployment

The backend ships as a Docker image (backend/Dockerfile) and runs on any Docker-capable host (Koyeb, Hugging Face Spaces, Railway, Render, Fly…). It binds $PORT, exposes GET /api/health, and auto-creates its schema on first boot — no migration step. See DEPLOY.md for the required env vars and per-host setup (Hugging Face Spaces, Koyeb, Railway…). A keepalive GitHub Action pings /api/health to keep sleep-prone free tiers warm.

About

Tech Stack

Features

Prerequisites

Deployment

Known Limitations

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