Express

Security notes, SOC lab write-ups and tested code by Mahir Faysal, a SOC Level 1 cybersecurity learner in Bangladesh, plus notes from my Next.js and Gemini projects. Sample posts are marked and drafts stay in the admin area.

All notes Coding tips · 150 Learning notes · 25 Practice · 1

Coding tips

Error: listen EADDRINUSE: address already in use in Node.js: 10 Causes and Fixes (Tested on Linux, Windows tips, nodemon)

EADDRINUSE means another process is already listening on the port your Node.js server wants. Here are 10 real causes, from a forgotten terminal to a Ctrl+Z'd process, nodemon orphans and IPv6 binding, with the exact commands and output from my tests.

November 5, 2026 · 14 min read · 6 views