Developer tools
Format and validate JSON, encode Base64, hash text, decode JWTs and more developer utilities. Free, in your browser, and nothing you paste is sent off.
All 12 tools
JSON validator
Find out whether it is valid JSON, and exactly where it is not.
Compare two JSON
See how alike two JSON documents are, and exactly where they differ.
Case converter
Convert text between camelCase, snake_case, kebab-case and the rest.
URL encoder and decoder
Escape text for a URL, or read an escaped one back.
Number base converter
Convert a number between binary, octal, decimal and hex.
Hash generator
Get the SHA-256 or SHA-512 fingerprint of any text.
JWT decoder
See what is inside a JSON Web Token, without sending it anywhere.
Unix timestamp converter
Turn a Unix timestamp into a readable date, and back.
Cron expression reader
Read a cron line in plain words before it runs.
UUID generator
Generate version 4 UUIDs, as many as you need.
Base64 encoder / decoder
Encode text to Base64 or decode it back, with full Unicode support.
JSON formatter
Format, validate and tidy JSON with clear error messages.
About these tools
Developer utilities that are usually reached for once, in the middle of debugging something else: validating JSON that an API returned, seeing what actually changed between two payloads, formatting something unreadable, and encoding or decoding base64.
The JSON validator uses a scanner written by hand rather than JSON.parse, because V8 stopped reporting the position of a syntax error in recent versions — and 'unexpected token' without a line number is not a useful thing to tell somebody staring at nine thousand lines. It reports the line, the column, and what it expected instead.
All of it is local, which is the reason to use these rather than the first result on a search engine. Debugging payloads routinely contain API keys, session tokens, customer records and internal hostnames, and pasting those into a stranger's website is a disclosure you cannot take back. Here the text is parsed by JavaScript already on your machine and never sent anywhere.