Practical reference for the developer utilities on OnlineTextLab — JSON formatters, diff checkers, regex testers, hash generators, JWT decoders, UUID generators, and more.
Paste raw JSON into the JSON Formatter to get a properly indented, readable version. The JSON Validator runs the same parse but reports the line and character position of syntax errors. Both tools process the input client-side using the browser's native JSON.parse, so behaviour matches what your JavaScript runtime would see.
Paste the original text in the left panel and the updated text on the right, then click Compare. The tool uses the Myers diff algorithm to highlight added lines in green and removed lines in red. Download the unified diff as a .diff file to share with teammates or attach to a pull request review.
Paste a JWT (three base64url-encoded segments separated by dots) into the JWT Decoder. It decodes the header and payload JSON client-side and displays them in formatted form. The signature is shown but not verified — for verification you need the secret or public key in your own environment.
Hash Generator produces MD5, SHA-1, SHA-256, and SHA-512 digests from any input string. SHA-256 and SHA-512 use the browser's SubtleCrypto API for cryptographic correctness. Use SHA-256 for checksums and content integrity; avoid MD5 and SHA-1 for security-sensitive purposes.
