Free Online Developer Toolbox
JSON formatter, Base64, word counter, timestamp converter, hash, UUID and more — the everyday tools developers need, all in one place. Everything runs locally in your browser: no data leaves your device, no install, no sign-up, completely free.
- 🔒 Data never leaves
- ⚡ Instant results
- 📱 Works on mobile
- 🆓 Completely free
All Tools
JSON Formatter
Beautify, minify and validate JSON in one click, with automatic error detection.
Base64 Encode / Decode
Convert text to and from Base64, with full UTF-8 and URL-safe support.
Word Counter
Instantly count words, characters, sentences, paragraphs and reading time.
Case Converter
Switch between UPPERCASE, lowercase, Title Case, camelCase, snake_case and more in one click.
URL Encode / Decode
Percent-encode and decode URL parameters with encodeURIComponent.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable date-time in real time.
Hash Generator
Generate SHA-1 / SHA-256 / SHA-384 / SHA-512 hashes.
UUID Generator
Batch-generate UUID v4 with one-click copy — great for testing and database keys.
QR Code Generator
Turn a URL or text into a QR code instantly and download it as PNG — free.
Password Generator
Generate strong random passwords with custom length and character sets, using cryptographic randomness.
JWT Decoder
Decode a JWT to read its header and payload, inspect claims and expiry.
Color Converter
Convert HEX, RGB and HSL color codes instantly, with a live preview.
Regex Tester
Test regular expressions live, highlight matches, with flags and capture groups.
Why choose DevToolbox?
🔒 Privacy first
Every operation runs on your device with JavaScript. Whatever you paste is never sent to a server or stored — safe for passwords, keys and sensitive text.
⚡ Blazing fast
Static pages on a global CDN load instantly, and every tool responds in real time without any round trips.
🧭 Simple to use
A clean interface with no clutter. Each tool comes with clear instructions and an FAQ, so beginners can start right away.
📱 Cross-device
Responsive design that works great on desktop, tablet and phone, with both light and dark mode.