Free online tools
Developer Tools
Format JSON, decode JWTs, hash strings, test regexes and generate QR codes — the utilities you usually grab from a dozen different sites, unified under one clean interface.
- 18
- Tools
- 17
- Live now
- 100%
- Free
All tools
Developer Tools
QR Code Generator
Generate QR codes for URLs, text or Wi-Fi.
JSON Formatter
Format and pretty-print JSON with indentation.
Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 back to text.
JWT Decoder
Decode JWT tokens and inspect header, payload and expiry.
UUID Generator
Generate random UUIDs (v4) in bulk.
Hash Generator
Generate SHA-1, SHA-256 and SHA-512 hashes.
Regex Tester
Test regular expressions with live match highlighting.
JSON Validator
Validate JSON and see exactly where errors are.
URL Encoder/Decoder
Encode or decode URL components safely.
Color Converter
Convert colors between HEX, RGB, HSL and HSV formats.
JSON Minifier
Minify JSON to the smallest possible size.
HTML Formatter
Format and beautify HTML markup.
CSS Formatter
Format and beautify CSS code.
JS Formatter
Format and beautify JavaScript code.
Markdown to HTML
Convert Markdown to clean HTML instantly.
HTML Minifier
Minify HTML by removing whitespace and comments.
CSS Minifier
Minify CSS to reduce file size.
JS Minifier
Minify JavaScript by stripping comments and whitespace.
About
Why developer tools exist
Development is full of micro-tasks — formatting a JSON response, decoding a JWT mid-debug, generating a UUID, testing a regex. Each is five seconds with the right tool and five minutes without.
These run entirely client-side, so they're safe for the things you'd never paste into a random website — tokens, keys, production payloads.
Which dev utilities matter most?
- ✓
JSON formatting — Unformatted payloads are unreadable — beautify first, debug second.
- ✓
Encoding/decoding — Base64, URL encoding and JWTs come up constantly in API work.
- ✓
Validation — A validator points at the exact broken character instead of you hunting for it.
- ✓
Generators — UUIDs, hashes and QR codes without adding a dependency to your project.
How it works
Three steps, zero friction
Pick a tool
Choose from the grid above — every tool opens instantly, no sign-up screen in the way.
→Drop or paste
Upload a file or paste your text. Everything is processed right in your browser tab.
→Copy or download
Get your result, copy it to the clipboard or download the file — done in seconds.
What you can do
Popular uses for Developer Tools
Debugging
Format JSON responses, decode JWTs and test regexes mid-debug.
Data wrangling
Encode, hash, validate and convert payloads between formats.
Ship faster
Generate QR codes, UUIDs and slugs without adding dependencies.
Clean code
Beautify minified files and validate syntax before committing.
Common mistakes
- ✗Pasting production secrets into server-based tools — always check if processing is local.
- ✗Debugging data by eyeball — a formatter finds the missing comma instantly.
- ✗Trusting output without spot-checking an edge case first.
Tips that actually help
- ✓Validate input before transforming it — most "bugs" are malformed data.
- ✓Prefer client-side tools for anything containing secrets or real tokens.
- ✓Bookmark your daily tools — they open faster than a terminal.
FAQ
Developer Tools — questions, answered
Is my code or data sent to a server?+
Never. Formatters, encoders, decoders and hash generators run entirely client-side — safe for JWTs, keys and sensitive payloads.
Do the tools handle large inputs?+
Yes — they process tens of thousands of lines instantly since there's no network round-trip. Extremely large files depend only on your device.
Can I use these tools offline?+
After the page loads, developer tools keep working without a connection — they're pure browser code with no API calls.
Is the output standard-compliant?+
Yes — formatters and encoders follow the official specs (RFC 8259 for JSON, RFC 4648 for Base64, and so on), so output works with any compliant parser.
Can I paste production tokens or keys?+
Yes — because nothing leaves the page. That said, verify "local processing" claims on any site by checking the network tab; here you'll see zero requests.