Locally generate random UUID v4 or UUID v7 with millisecond timestamps, 1–1000 at a time. Supports quick quantity and case selection, and copying one by one or all.
v4 uses crypto.randomUUID; v7 uses a 48-bit millisecond timestamp and a 74-bit cryptographic random number that reveals the generation time. Incrementation is not guaranteed to the same millisecond or when the clock is rolled back; neither version is guaranteed to be absolutely unique.
Shortcut key: Ctrl/⌘+Enter. Modifying inputs or options clears old results.
x is a hexadecimal number; y is one of 8, 9, a, or b. This is just a format description.
v4 is a random identifier; the first 48 bits of v7 are the Unix millisecond timestamp, and the remaining valid random bits are 74 bits, which is suitable for roughly sorting by time, but will reveal the generation time. Increments are not guaranteed within the same millisecond and when the clock is rolled back. v1 is not supported.
The probability of collision is extremely low, but it is not a mathematical guarantee of absolute non-repetition. Appropriate unique constraints should still be established when used in databases.
v4 calls crypto.randomUUID(); v7 writes the 48-bit Unix millisecond timestamp, version and variant bits according to RFC 9562, and uses crypto.getRandomValues to generate 74-bit random data. v7 does not provide strict monotonicity within the same millisecond, and clock rollback may also disrupt ordering; neither is an absolute and unique guarantee.
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