websystemer / Security / UUID & ULID
UUID & ULID Generator and Inspector
Generate UUID v4, UUID v7 and ULID in bulk, and inspect any UUID or ULID to see its version and creation time. Runs in your browser.
About UUID & ULIDhow it works and good to know
Which one should I use?
UUID v4 is 122 random bits: the safe default when you only need a unique id. UUID v7 starts with a millisecond timestamp, so ids sort by creation time and database indexes stay compact; use it for primary keys. ULID is the same idea in 26 characters of Crockford base32, easy to read and to put in a URL.
Ordering
Several v7 or ULID values made in the same millisecond still sort in the order they were created. A counter handles the burst, and the clock moves forward by one millisecond if the counter runs out.
Inspect
Paste any UUID (with or without hyphens or braces) or a ULID to see its version, variant and, for v1, v6, v7 and ULID, the time it was created.
Privacy
Ids are made with your browser's crypto.getRandomValues. Nothing is sent anywhere, and nothing is stored.
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