Debugging WebSocket Issues

Overview

WebSocket "invalid frame header" errors often stem from raw HTTP being written to an upgraded socket, not actual frame corruption. The most common cause is multiple WebSocketServer instances conflicting on the same HTTP server.

When to Use

• Error: Invalid WebSocket frame: RSV1 must be clear
• Error: WS_ERR_UNEXPECTED_RSV_1
• Error: Invalid frame header
• WebSocket connects then immediately disconnects with code 1006
• Server logs success but client receives garbage data

Quick Reference