Free Developer Tools
Format, validate, encode, minify and generate in one place.
Everything here runs in your browser, so pasted code stays on your device.
Most used
- JSON FormatterPretty-print or minify JSON with 2 spaces, 4 spaces or tabs, sort keys, and see exact error positions.Open tool
- QR Code GeneratorCreate QR codes for URLs, text, Wi-Fi, email, phone and contact cards, with colours, error correction and PNG or SVG download.Open tool
- Password GeneratorGenerate strong random passwords or word passphrases with unbiased cryptographic randomness and an entropy estimate.Open tool
All developer tools (15)
JSON Formatter
Pretty-print or minify JSON with 2 spaces, 4 spaces or tabs, sort keys, and see exact error positions.
JSON Validator
Validate JSON against RFC 8259 with precise error positions, duplicate-key detection and structure stats.
HTML Formatter
Beautify and re-indent HTML with control over indent size, line wrapping, attributes and blank lines.
CSS Minifier and Beautifier
Minify CSS with CSSO (optional restructuring) and see the size saved, or beautify minified CSS back to readable code.
JavaScript Minifier
Minify JavaScript with Terser in your browser, with mangle, compress and keep-names options and exact error positions.
Base64 Encoder and Decoder
Encode and decode Base64 with correct UTF-8 handling, URL-safe output, and file to data URI conversion.
URL Encoder and Decoder
Percent-encode or decode text for URLs in component or full-URL mode, and break a URL into its parts and query parameters.
UUID Generator (v4 and v7)
Generate random v4 or time-ordered v7 UUIDs in bulk with formatting options, and validate or inspect any UUID.
QR Code Generator
Create QR codes for URLs, text, Wi-Fi, email, phone and contact cards, with colours, error correction and PNG or SVG download.
Password Generator
Generate strong random passwords or word passphrases with unbiased cryptographic randomness and an entropy estimate.
Color Palette Generator
Build complementary, analogous, triadic, tetradic and monochrome palettes from one colour, with contrast checks and CSS export.
HEX to RGB Converter and Contrast Checker
Convert colours between HEX, RGB(A), HSL and OKLCH with a live preview, and check WCAG contrast between two colours.
CSS Gradient Generator
Design linear, radial and conic CSS gradients with draggable colour stops, presets and ready-to-copy CSS.
Open Graph Preview and Checker
Check a page's Open Graph and Twitter card tags, preview generic social cards and list missing or broken tags.
Email Signature Generator
Build a professional HTML email signature with a live preview, then copy it into Gmail, Outlook or Apple Mail.
About these developer tools
Format and validate JSON, minify CSS and JavaScript, encode Base64 and URLs, generate UUIDs, passwords and QR codes, and work with colours and gradients.
Everything runs locally in your browser, so pasted code, tokens and passwords are never sent anywhere.
Questions
Are generated passwords secure?
They use the browser’s cryptographically secure random number generator with unbiased sampling, and they never leave your device.
Is it safe to paste private code here?
The developer tools process input in your browser. Only the Open Graph preview fetches a public URL on our server when you ask it to.