UUID Generator

UUID Generator makes unique IDs for databases, APIs, files and test data. Choose a random UUID version 4, a time-ordered UUID version 7, a ULID or a short NanoID, say how many you need from 1 to 10,000, and copy them or download a text file. Formatting options give you uppercase, no hyphens, Microsoft-style braces, a urn:uuid: prefix, or quoted, comma-separated lists ready to paste into code.

Version 7 is the newer choice for database keys: it starts with the time, so new rows land at the end of an index instead of all over it. Our v7 follows the RFC 9562 layout exactly and keeps IDs made in the same millisecond in order, so a batch of 10,000 sorts the way it was made. ULIDs do the same job in 26 easy-to-read characters.

Every ID is made in your browser from its cryptographic random number generator, the same source used for encryption keys, and nothing is sent anywhere. The checker underneath reads any UUID, GUID or ULID and tells you its version, its variant and, for time-based ones, exactly when it was made.

1. Choose UUID v4, UUID v7, ULID or NanoID at the top. For NanoID, set the length and pick which characters to use.
2. Type how many you want, or press one of the quick amounts: 1, 10, 100, 1,000 or 10,000.
3. Open “Format” to change letters to UPPERCASE or lowercase, drop the hyphens, add braces or a urn:uuid: prefix, wrap each ID in quotes, or separate them with commas.
4. Press Copy (or click a single ID) to copy, or Download .txt to save the list. Press Generate new for a fresh set.
5. To check an ID, paste it into “Check or decode an ID” and read its version, variant and timestamp.

• UUID v4 with 122 random bits, using the browser’s crypto.randomUUID where available.
• UUID v7 with a 48-bit millisecond timestamp, correct version and variant bits, and a 12-bit counter that keeps same-millisecond IDs in order.
• ULID in Crockford Base32 (no I, L, O or U), with the random part counting up inside one millisecond as the ULID spec describes.
• NanoID of 2–256 characters from six ready alphabets or your own, without the bias that a simple remainder would add, plus a live strength estimate in bits.
• Bulk generation of up to 10,000 IDs in well under a second, with the size of the list shown.
• Output formats: standard, uppercase or lowercase letters, with or without hyphens, {braces}, urn:uuid:, double or single quotes, and new line, comma or comma-and-line separators.
• A checker for UUIDs (any common form) and ULIDs: version 1–8, variant, nil and max UUIDs, and the creation time for v1, v6, v7 and ULID.

• For database primary keys, prefer v7 or ULID: they sort by time, which keeps indexes compact. Use v4 when you don’t want an ID to reveal when it was made.
• A v7 UUID or ULID shows its creation time to anyone who reads it. Don’t use them where that would leak something private.
• Version 1 UUIDs may contain the network card address of the computer that made them; the checker says when the address is a random stand-in instead.
• Some systems, such as Microsoft SQL Server and .NET, write GUIDs in uppercase with braces. Pick UPPERCASE and Braces to match.
• For short links or invite codes, a 10–12 character NanoID from “No look-alikes” is easy to read aloud and type without mistakes.