Developer Tools
Format, validate, decode and work with everyday developer data — directly in your browser.
All tools
- JSON Viewer Format, validate and minify JSON, with a collapsible tree and exact error locations.
- XML Viewer Pretty print or minify XML, check it is well-formed, and explore it as a tree.
- HTML Viewer Beautify or minify HTML and see a safe, sandboxed preview of the page.
- Regex Tester Test regular expressions with live highlighting, capture groups and ready-made patterns.
- JWT Decoder Read a JWT's header and payload, with claims and expiry times explained.
- Base64 Encoder / Decoder Encode and decode Base64 with full Unicode support, URL-safe mode and files.
- URL Encoder / Decoder Percent-encode or decode URLs and parameters, and see every part of a URL.
- UUID Generator Generate secure random v4 UUIDs in bulk, and check any UUID's version.
- Hash Generator SHA-256, SHA-384, SHA-512 and SHA-1 for text or files, with checksum comparison.
- Timestamp Converter Epoch time to date and back, in seconds or milliseconds, UTC or local time.
Small tools for everyday work
Tidy up an API response, check a config file, see what a token contains or turn a log timestamp into a readable date. Each tool does one job, explains problems in plain language and shows where they are. Nothing you paste leaves your device.
Frequently asked questions
Is my data sent to a server?
No. Every tool here runs in your browser with JavaScript. What you paste is never uploaded, logged or stored — not in a database, cookies or local storage. You can even disconnect from the internet after the page has loaded and the tools keep working.
Are the tools free?
Yes. There is no sign-up, no limit and no watermark.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox and Safari on desktop and mobile. The hash generator needs a secure (https) page, which this site is.
Why does each tool have its own page?
So you can bookmark or share the exact tool you need, and so each page can explain its own format properly. The tab strip at the top moves between them.