Developer tools
UUID Generator
Generate up to 1,000 UUIDs v4, v7 (timestamped, sortable), v1, v5 or v3 in one click, with format options, and inspect any UUID to read its version, variant and date.
How to use this tool
- 1
Pick the version and the quantity (1 to 1,000).
- 2
Set the format (uppercase, hyphens, braces); for v5 or v3 choose the namespace and enter the names.
- 3
Click “Generate” to draw another batch, then copy or download the list.
- 4
Paste a UUID into the inspector to learn its version and date.
Help
- v4 is the usual choice: 122 random bits from the browser's secure generator. v7 starts with the time in milliseconds; UUIDs in a batch are sorted, which speeds up database indexes.
- v5 (SHA-1) and v3 (MD5) are deterministic: a namespace (DNS, URL, OID, X.500 or your own UUID) and a name always give the same identifier. One name per line to produce several.
- v1 timestamps in 100 ns steps; the “node” here is a random number, never your machine's MAC address.
- Uppercase, removing hyphens and braces can be toggled on the fly; copy everything or download a .txt.
- The inspector reads a pasted UUID (with or without hyphens, braces, urn:uuid:): version, variant and, for v1, v6 and v7, the creation date.
Frequently asked questions
Can two v4 UUIDs be identical?
In theory yes, in practice no: with 122 random bits you would need billions of billions of UUIDs before a collision becomes plausible.
Why use v7 rather than v4 as a database key?
A v7 starts with the time: new UUIDs append to the end of the index instead of scattering, which reduces fragmentation and speeds up writes. The downside: it reveals the creation date.
Is a UUID a secret?
No. A UUID identifies, it does not protect: do not use one as a password or access token.
Written and verified by the MaxyTools team · Updated on
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