About this tool
Tests need unique IDs for request bodies, idempotency keys, correlation headers and database fixtures. This generator creates random version 4 UUIDs with the browser’s crypto.randomUUID and time-ordered version 7 UUIDs built as RFC 9562 specifies: a 48-bit Unix millisecond timestamp, the version and variant bits, and cryptographically random bits. The inspector validates any UUID you paste, tells you its version and variant, and decodes the creation time for v1, v6 and v7, which is handy when you are reading IDs out of logs.
How to use it
- Pick v4 (random) or v7 (time-ordered) and how many you need, up to 500.
- Optionally switch to uppercase, remove hyphens or wrap values in braces for formats such as .NET GUIDs.
- Copy all values or download them as a text file.
- Paste any UUID into the inspector to validate it and, for time-based versions, see when it was created.
UUID Generator FAQ
When should I use UUID v7 instead of v4?
Use v7 when IDs are used as database keys or need to sort by creation time: because they start with a timestamp, new rows are inserted close together in B-tree indexes. Use v4 when the ID must not reveal anything, since v7 exposes its creation time to anyone who reads it.
Are v7 UUIDs generated here in order?
Yes. Within the same millisecond the 12-bit rand_a field is used as a counter (the monotonic method described in RFC 9562 section 6.2), so a bulk list sorts in generation order.
Does the validator accept uppercase or IDs without hyphens?
Yes. It accepts any case, with or without hyphens, braces or a urn:uuid: prefix, and shows the canonical lowercase form. It will flag hyphens in the wrong positions and non-standard variants, which are worth catching in an API that claims to return RFC-compliant UUIDs.