I Built 22 Free Developer Tools in a Weekend — Here's What I Learned

The Idea I kept bookmarking random utility sites — one for JSON diff, another for regex testing, another for Base64 encoding. Each had different UIs, aggressive ads, and some even sent my data to their servers. So I built mydevtools.dev — 22 developer tools in one place, with a consistent VS Code-style dark theme, and everything processing 100% in the browser. ## What's Inside ### Data & Text JSON Diff — Side-by-side comparison using Monaco Editor JSON Formatter — Beautify, minify, validate Text Diff — Line-by-line text comparison CSV to JSON — Bidirectional conversion JSON to YAML — Bidirectional conversion Word Counter — Words, characters, sentences, reading time ### Encoding & Conversion Base64 Encoder/Decoder — Full UTF-8 support URL Encoder/Decoder — With query string parser HTML Entity Encoder — Escape/unescape HTML Number Base Converter — Binary, octal, decimal, hex ### Security & Identity JWT Decoder — Header, payload, expiration check Hash Generator — MD5, SHA-1, SHA-256, SHA-