54 tools · free · offline
Developer tools that respect your privacy
Free online developer tools: JSON, SQL, YAML, XML formatters, encoders, generators and more. Everything runs in your browser — no data ever leaves your machine.
Pick a tool from the left menu to begin.
What's inside
Tools are grouped by function — open the left menu to see them all.
Text & Data
- JSON Formatter & Validator
- XML Formatter
- HTML Formatter & Preview
- YAML Formatter & Validator
- YAML ⇄ Properties Converter
- Case Converter
- Text Diff Checker
- Comma Separator
- Join Lines (Text to One Line)
- Regex Generator & Tester
- JSON to TypeScript Converter
- JSON to Java Class / Record Generator
- .env to JSON / YAML Converter
- Find and Replace Text
- JSON to XML Converter
- URL Parser & Query String Viewer
- JSON Diff & Compare
SQL & Database
Encoding & Security
Generators
Everyday Utilities
- Word & Character Counter
- Remove Vietnamese Accents
- Number to Words Converter
- Password Generator
- Unit Converter
- Percentage Calculator
- Date Difference Calculator
- Remove Duplicate Lines
- CSV to JSON Converter
- Markdown to HTML Converter
- Image Converter (JPG, PNG, WebP)
- QR Code Generator
- Excel Converter (XLSX to JSON / CSV)
- Image to PDF Converter
100% in-browser
Everything you type is processed locally — not a single byte is sent to a server. Total privacy.
Fast & distraction-free
No sign-up, no waiting. Open a tool, paste your data, get syntax-highlighted results instantly.
Backend-dev focused
Prioritising tools for JSON, SQL, PostgreSQL, JWT and encoding — exactly what you reach for while coding.