JSON, Base64, URL & Regex Tools
Format and check JSON, encode and decode Base64 and URLs, and test regular expressions with live highlighting.
Study & coding100% freePrivate
Everything runs in your browser. What you type is not sent anywhere.
How to use JSON, Base64, URL & Regex Tools
- 1Pick JSON, Base64, URL or Regex.
- 2Paste or type your text.
- 3Read the result, fix any mistakes it points out, and copy it.
Frequently asked questions
Does my text leave my device?
No. Everything is worked out in your browser, so it is safe to paste your own code or sample data. Do not share real passwords or keys anywhere online anyway.
How does the JSON checker help?
If the JSON is wrong, it tells you the line and column of the first problem, in plain words, so you can fix it quickly.
Is Base64 a way to keep things secret?
No. Base64 only changes how data is written. Anyone can decode it, so never use it to hide passwords.
What if my regex is very slow?
Some patterns take forever on certain text. The tester runs in a separate worker and stops itself after a short time, so the page does not freeze.