A version 4 UUID is 122 bits of randomness formatted as 8-4-4-4-12 hex characters. Collisions are practically impossible, which makes them ideal for test fixtures, idempotency keys and identifiers created on a client before a database has assigned one.
What you'll learn
- Generate single or bulk UUIDs
- Understand the format and the version digit
- Know the trade-offs against sequential IDs
Step by step
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Choose how many
Open the UUID Generator and pick a count. One for a quick placeholder, more for a fixture file.
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Click Generate
Each value comes from crypto.randomUUID(), the browser's cryptographically secure generator. The third group always starts with 4, the version.
41a622e9-6245-4ac9-9d3d-01fe7929f5ce
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Copy All
Values are copied one per line, ready for a seed script or a spreadsheet column.
Common problems
I need sortable IDs
v4 UUIDs are random and sort poorly as database keys. Consider UUID v7 or ULIDs, which embed a timestamp, when insert order matters.
FAQ
Can two generated UUIDs collide?
The probability is negligible; you would need to generate billions per second for years to expect one.
Are the values sent anywhere?
No. They are generated in your browser and exist only on the page until you copy them.