How I Built a Real-Time Minecraft Server Status Checker with Next.js 15 and Server-Sent Events

I needed to build a real-time Minecraft server status checker for Minecraft ServerHub — a server list with 1,000+ servers. The naive approach (polling an API every few seconds) felt wasteful. So I went with Server-Sent Events (SSE) to stream results back to the client as soon as they arrive. Here's exactly how it works, including the raw TCP protocol implementation. The Minecraft Server List Ping Protocol Minecraft Java servers use a custom binary TCP protocol for status pings. You have to: Open a raw TCP socket to port 25565 Send a Handshake packet (packet ID 0x00 ) to set up the connection Send a Status Request packet (packet ID 0x00 again, but in the Status state) Read the Status Response — a JSON payload with player count, version, MOTD, etc. The binary format uses variable-length integers (VarInts) — each byte uses 7 bits for data and 1 bit to indicate if more bytes follow. The SSE API Route (Next.js 15 App Router) Instead of blocking until we have a result, the API route opens th