Developer Tools Collection
20+ Free online tools for developers
All tools run locally in your browser. No data sent to server. Fast, secure, and privacy-focused.
QR Generator
Generate QR codes from text, URLs, and more
QR Scanner
Scan and decode QR codes from images
URL Parser
Parse and analyze URL components
JSON Formatter
Format, validate and beautify JSON
Markdown Renderer
Preview and render Markdown text
JWT Decoder
Decode and verify JWT tokens
Base64 Converter
Encode and decode Base64 strings
Hex Converter
Convert between hex and text
Escape Decoder
Decode HTML and URL escape sequences
Hash Calculator
Generate MD5, SHA1, SHA256 hashes
UUID Generator
Generate UUID v1, v4 identifiers
Random Number Generator
Generate random numbers in range
Random String Generator
Generate random strings with custom patterns
Block Puzzle Solver
Solve block sliding puzzles
ZIP Tool
Compress and extract ZIP files
Subtitle Formatter
Parse and format subtitle files (SRT, VTT, ASS, LRC) into readable text
Minesweeper
Classic mine sweeping puzzle game with multiple difficulty levels
24 Game Solver
Find all solutions to make 24 using four numbers and basic operations
Chinese Chess (Xiangqi)
Play Xiangqi online: vs AI engine (5 difficulty levels) or local two-player, with game clocks and move records
Chess
Play chess online: vs Stockfish AI (5 difficulty levels) or local two-player, installable as an offline-capable app
WebClip
Secure cross-device clipboard sharing with end-to-end encryption
About Dev66
Dev66 provides a comprehensive collection of developer tools that work entirely in your browser.
All tools are open source and available for free. No registration required, no data collection.
Need help or want to suggest new tools?
Create an Issue on GitHub