UUID, ULID & Nano ID Generator

About this tool

Unique identifiers let programs name records without asking a central server. This tool makes four kinds. UUID v4 is 122 random bits in the familiar 8-4-4-4-12 form, the all-round choice. UUID v7 (RFC 9562) starts with a 48-bit timestamp in milliseconds followed by random bits, so values sort in the order they were created, which keeps database indexes tidy; ids made in the same millisecond are counted up so that the order is still right. ULID is a similar time-ordered identifier in a shorter 26-character form written in Crockford Base32, which avoids look-alike letters, and it also counts up inside a millisecond. Nano ID is a compact random string of letters, digits, underscore and hyphen, 21 characters by default, made to be URL-safe and short; you can choose its length from 4 to 64. Everything is generated with your browser's secure random number generator, and nothing is sent anywhere. We checked the output by decoding it with Python's own libraries: the uuid module confirmed the version and variant of 200 v4 and 50 v7 values and the timestamp stored in every v7 value, python-ulid read back the timestamps of 60 ULIDs, a sorted list of ids made in order came out in the same order, and the Nano ID alphabet is spread evenly over 84,000 characters. Be aware that time-ordered ids reveal when they were created, so use v4 or Nano ID where that matters, and none of these identifiers is a secret or an access token by itself.

How to use it

1. Choose the type of identifier.
2. Set how many you need, up to 500.
3. Choose hyphens and case for UUIDs, or the length for Nano IDs.
4. Press Generate and copy the result.

Common problems

Which one should I use

Use UUID v4 when you just need unique values, v7 or ULID when you want them to sort by creation time (database keys), and Nano ID when you want short URL-friendly strings.

Can I use them as passwords or tokens

No. They are meant to be unique, not secret. For tokens and passwords use the password generator, which is designed for that.

Two ULIDs made at once look almost the same

That is by design: within the same millisecond only the end of the random part is counted up, so that they sort in the order they were made.

My system wants uppercase or no hyphens

Tick Uppercase UUIDs, or untick UUID hyphens, to match the format your system expects.