Developer Tools
A curated collection of essential developer utilities that run entirely in your browser. Format and validate JSON, encode and decode Base64, generate hashes, compare text diffs, test regular expressions, and convert between data formats — all without sending a single byte to any server. Every tool is free, requires no sign-up, and works offline once loaded. Whether you are debugging an API response, preparing data for a migration, or writing documentation, these tools save you from context-switching to the terminal or installing yet another CLI package.
15 free tools — all running privately in your browser
Base64 Encoder/Decoder
Encode to and decode from Base64 format
CSV to JSON Converter
Convert CSV data into structured JSON format
CSV to SQL Converter
Generate SQL insert statements from CSV data
JSON Formatter
Prettify, format, and validate JSON data
JSON to CSV Converter
Convert structured JSON data into CSV format
Timestamp Converter
Convert Unix timestamps to human-readable dates
URL Encoder/Decoder
Encode and decode URL strings
JSON to YAML Converter
Convert JSON data to YAML format instantly
YAML to JSON Converter
Convert YAML data to JSON format instantly
HTML Encoder/Decoder
Encode and decode HTML special characters and entities
JWT Decoder
Decode and inspect JWT token header, payload, and expiration
Cron Expression Parser
Parse cron expressions to plain English with next run times
JSON Diff Viewer
Compare two JSON objects and highlight differences
Regex Tester
Test regular expressions with real-time match highlighting
Markdown to HTML
Convert Markdown to HTML with live preview