Developer Tools

A fast, no-nonsense toolkit for everyday development tasks. Prettify and validate JSON, encode and decode Base64, inspect a JWT, generate UUIDs, hash a string or test a regular expression with live highlighting. Everything runs client-side, so you can safely paste tokens and payloads without them ever touching a server.

JSON Formatter Prettify, minify and validate JSON. Live

SQL Formatter Beautify and format SQL queries. Live

Base64 Encode Encode and decode text or files. Live

JWT Decoder Inspect token header and payload. Live

UUID Generator v4 IDs, one or a thousand. Live

Hash Generator SHA-1, SHA-256, SHA-384 and SHA-512 digests. Live

Regex Tester Match and highlight in real time. Live

Cron Expression Generate and parse crontab schedules. New

Code Beautifier Clean up and minify HTML, CSS and JS. New

HTML Entities Encode and decode HTML entities. New

String Escape Escape and unescape JSON/JS strings. New

Markdown Table Visual grid to GitHub flavored table. New

URL Parser Break down URLs into protocol, host, and params. New

AI Token Counter Count GPT, Claude & Gemini tokens as you type. New

Why use these developer tools?

Every tool in this collection runs entirely in your browser. That means there's nothing to install and nothing to sign up for, and crucially, the files and text you work with never leave your device — no uploads, no accounts, no tracking. Just open a tool and get the job done.

Browse the full set of ToolNest tools, or jump straight to the one you need above.