UUID Generator
Make UUIDs, ULIDs or NanoIDs, one or a thousand.
Questions
Version 4 or version 7?
Version 4 is fully random and the most widely used. Version 7 starts with the current time, so new IDs sort after older ones, which keeps database indexes efficient. Both are standardized in RFC 9562.
What are ULIDs and NanoIDs?
A ULID is 26 characters: the creation time to the millisecond, then 80 random bits, written in Crockford’s base 32 (no I, L, O or U, so it reads aloud without confusion). ULIDs sort by time like version 7 UUIDs; several made in the same millisecond count up so they stay in order. A NanoID is a short random ID, 21 URL-safe characters by default, with about as much randomness as a version 4 UUID (126 bits against 122).
Are these UUIDs really unique?
A version 4 UUID has 122 random bits from your browser’s cryptographic generator. You would need to create about a billion per second for 85 years to have a 50% chance of one duplicate.
Is a UUID the same as a GUID?
Yes. GUID is Microsoft’s name for the same thing. Some Microsoft tools write them in capitals with braces, which the options can do too.
Can I use a UUID as a password or secret token?
A version 4 UUID is random enough to be hard to guess, but it isn’t designed as a secret. Version 7 UUIDs reveal when they were created. Use a proper token generator for secrets.
Is it free? Do I need an account?
It is free to use and there is nothing to sign up for. There are no watermarks and no daily limits.
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