Generate time-ordered UUIDv7 identifiers (RFC 9562) or classic random v4s by hand with Web Crypto. Everything runs in your browser.
Identifiers are generated locally with the Web Crypto API. Nothing ever leaves your device.
The timestamp under each v7 is decoded from its first six bytes — Copy takes only the UUID itself.
UUIDv7 is defined by RFC 9562 and this page builds it by hand from crypto.getRandomValues — no libraries. The trick that separates it from v4 is where the bytes go: a wall-clock timestamp is moved to the front of the identifier, so the string's own sort order becomes creation order. The version toggle also lets you mint classic random v4 UUIDs for comparison, and the timestamp printed beside each v7 is decoded back from its first six bytes.
Reach for v7 when IDs live in a sorted index — a Postgres primary key, a B-tree or LSM-tree table like MySQL InnoDB, RocksDB or DynamoDB sort keys. Because v7s sort lexicographically in the same order they were created, new rows append to the end of the index instead of scattering writes across it. Reach for v4 when the value must be unguessable and time must not leak: public identifiers for URLs and security tokens still favor v4's larger random tail and zero timestamp.
The first 48 bits of every v7 UUID are the creation time — milliseconds since the Unix epoch — written most-significant byte first. Sorting UUID strings compares from the left, so the timestamp dominates the comparison: '0198…' rows always sort before '0199…' rows, and lexicographic order equals chronological order. The random bits that follow only decide the order of UUIDs minted inside the same millisecond.
Yes, within the same millisecond: after the 48-bit timestamp and the 6-bit version and variant markers, 74 bits are left random — about 1.9 × 10^22 possibilities per millisecond of creation time. That is far beyond what one machine emits in a millisecond, so collisions remain a theoretical curiosity. If you need strict same-millisecond monotonicity guarantees, use a server library that implements RFC 9562's optional monotonic-count scheme; this browser tool relies on the random bits.
Each UUID is stamped with the clock at the moment it is created, so batches generated in one click share a millisecond very often — the browser loop runs faster than the clock ticks. That is normal and harmless: the timestamps shown next to the IDs are real, and the random tail keeps every ID in the batch distinct.
No. The identifiers are assembled in your browser from the Web Crypto API and your system clock. Nothing is transmitted, stored or logged anywhere, and the batch disappears when you close the tab.
If you just finished with UUID v7 Generator, the natural next steps are ASCII Banner, Barcode Generator, WiFi QR Code, or browse every tool in Daily Tools.