UUID Generator (v4, v7 & v1)

This free online UUID generator creates up to 5 million identifiers in one batch, right in your browser. Pick version 4 (random), version 7 (time-ordered) or version 1 (timestamp), set the quantity, then copy the list or save it as a text file.

A UUID is a 128-bit identifier written as 32 hexadecimal digits in five groups (8-4-4-4-12), for example 0192f0c4-7a1e-7c3b-9d2e-5b8f1a2c3d4e. GUID is Microsoft's name for the same format; select Uppercase and Braces to get the style used in .NET and the Windows registry.

Version 4 is drawn from your browser's crypto API and is the right default for IDs that should not reveal when they were created. Version 7 starts with a millisecond timestamp, so values roughly sort by creation time — useful for indexed database keys. Version 1 uses a timestamp plus a randomly generated node ID, never a real MAC address. Generation runs entirely in your browser.

Features:

Versions: v4 (random), v7 (time-ordered) or v1 (timestamp)
Quantity: 1 to 5,000,000 per run; above 100,000 the list is saved straight to a .txt file after confirmation
Uppercase: switch the letters to upper case
Hyphens: keep or remove the separators, giving 36 or 32 characters
Braces: wrap each UUID in { }
Trailing comma: add a comma to every line except the last, ready for a SQL IN list or an array
Quotes: wrap each line in single or double quotes
Prefix and suffix: add fixed text to every line
Copy, save and clear, with line numbers and a live line indicator in the editor

FAQ:

Q: Which version should I use, v4, v7 or v1?
A: Use v4 for general-purpose IDs: it is almost entirely random and reveals nothing about when or where it was made. Use v7 when UUIDs go into an indexed database column, because the leading timestamp keeps new rows near the end of the index. v1 is the legacy timestamp-based format, useful when you need to match older systems. Switching versions does not change any of the formatting options.
Q: Are v7 UUIDs strictly ordered?
A: Not within the same millisecond. The first 48 bits come from Date.now(), so values made later sort after earlier ones, but several UUIDs generated in one millisecond are randomised and may come out in any order. If you need a guaranteed sequence, add your own counter.
Q: Does removing the hyphens change the UUID?
A: No, it only changes how the value is written. With Hyphens off you get the same 128 bits as 32 hex characters instead of the usual 36-character form; the version and variant bits are untouched.
Q: Why is there no comma on the last line?
A: Because the output is usually pasted into a SQL IN list or a code array, where a trailing comma would be a syntax error. The comma is added to every line except the last one.
Q: In what order are braces, quotes, prefix and suffix applied?
A: In a fixed order: upper case first, then hyphens removed, then { } around the UUID, then prefix and suffix, then quotes around the whole line, and finally the comma. Braces therefore wrap only the UUID, while quotes wrap the prefix and suffix too.
Q: What happens with very large batches?
A: Up to 10,000 UUIDs are generated in one go. Between 10,000 and 100,000 the list is built in chunks with a progress indicator so the page stays responsive. Above 100,000 you are asked to confirm and the result is saved directly as a .txt file instead of being put in the editor. The hard limit is 5,000,000.
Q: Is a GUID different from a UUID, and can two results be identical?
A: GUID is just Microsoft's name for the same 128-bit format. v4 values come from your browser's crypto API (with a Math.random fallback in very old browsers), while v1 and v7 mix a timestamp with random bits. Collisions are astronomically unlikely, but the tool does not check the generated list for duplicates.

Common uses:

Primary keys and seed data for databases; v7 keeps B-tree indexes compact
Test fixtures, mock API responses and sample records
Request IDs, trace IDs, session IDs and file names
SQL INSERT values and code arrays, using the comma and quote options

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