Developer Guides
Short explainers that pair with StackTools utilities. Learn the concept, then try it in the browser.
JavaScript Event Loop: Microtasks vs Macrotasks
Why Promise.then runs before setTimeout(0) — with a live visualizer.
How JWT Works (and How to Decode Safely)
Header, payload, signature — and what decoding does not prove.
Format & Validate JSON Online
Pretty-print, minify, and catch syntax errors quickly.
Base64 Encode & Decode Explained
Encoding vs encryption, data URLs, and JWT segments.
Convert curl to fetch / Axios
Turn DevTools “Copy as cURL” into maintainable JS.
Regex Cheatsheet for Developers
Common patterns, flags, and traps in JavaScript RegExp.