What Is This? Data Type Detector
Paste something you do not recognise. Tooltern tells you what it is, shows the key facts, and opens it in the right tool.
The local detector never sends your text anywhere. Ask AI is optional: it sends the first 1,500 characters once to our server and a classification model, which return a label only. Nothing is stored or logged. Do not paste live secrets.
How it works
As you type, a detector in your browser checks the text against the exact rules for each format: a JWT is three Base64URL segments starting with eyJ, a UUID has five hex groups of 8-4-4-4-12, a Unix timestamp is a 10 or 13 digit number in a plausible date range, a cron line has five schedule fields, and so on. It shows the best match with a confidence, the key facts (a UUID's version, a timestamp's date, a hash's likely algorithm, what Base64 decodes to) and any other formats it could be.
Press Open in… to jump to the matching tool with your text already filled in. The text is handed over through your browser's session storage, which never leaves your device and is cleared as soon as the next page reads it.
When the detector is unsure, or you want a second opinion, Ask AI to double-check sends the first 1,500 characters once to a classification model. It does not write text or keep anything: it returns only a label from a fixed list and a probability for each, shown as bars. The local rules always run first and work offline, so the AI is a tie-breaker, not a dependency.
Questions
Is what I paste sent anywhere?
Not by the local detector, which runs entirely in your browser. Only if you press Ask AI is the text sent, once, to classify it; it is not stored or logged on our side.
How can it tell MD5 from SHA-256?
By length: MD5 is 32 hex characters, SHA-1 is 40, SHA-256 is 64 and SHA-512 is 128. Different algorithms can share a length, so the tool lists the common candidates rather than pretending to be certain.
Why does a plain number show as a timestamp?
Ten-digit numbers between 1990 and 2100 are almost always Unix timestamps in seconds, and 13-digit ones in milliseconds. If you meant an ordinary integer, the alternatives line offers the number converter too.
Is there a limit on AI checks?
Yes, a few per minute per visitor and a daily total for the site, to keep it fast and free. When the limit is reached the local detector carries on working.