Developer tools
Formatting, encoding and decoding the things you paste between one window and another. All of it runs in your own browser, and nothing is uploaded.
JSON formatter & validator
Indent it, shrink it, or find out what is wrong with it
{"b":1,"a":[2,3]}Formatted, 2-space indent
Base64 encoder / decoder
Both directions, both alphabets, Unicode included
foobarZm9vYmFy
URL encoder / decoder
Percent-encoding, with the component and whole-URL rules apart
a b&c=da%20b%26c%3Dd
Robots.txt tester
See which rule a crawler actually applies
A Googlebot group beside a catch-allGooglebot ignores the catch-all
UUID generator
Version 4 and version 7, from your browser's own randomness
5 of version 4Fresh from crypto.getRandomValues
JWT decoder
Read the claims. It does not check the signature.
A three-part tokenHeader and claims, unverified