UUID v4
Generate a batch of random version-4 UUIDs, one per line. Each is 16 random bytes formatted as 8-4-4-4-12 hex with the correct version and variant bits set. Ask for up to 50 at once for seeding databases, test fixtures or correlation IDs.
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💡 Good to know: A random UUID has 122 bits of randomness — you'd have to generate a billion per second for 85 years for a 50% shot at one collision.
Worked example
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Inputs
- How many
5
Frequently asked
What is a v4 UUID?
A 128-bit identifier that is almost entirely random, with fixed bits marking it as version 4 (random).
Could two collide?
A version-4 UUID carries 122 random bits, so a duplicate is not impossible — it is a bet on a number so large the bet always wins in practice. That only holds when the bits are genuinely random: each UUID here takes its own fresh bytes from your browser's cryptographic random source, rather than all of them coming from one shared seed.