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UUID Generator

Generate cryptographically random UUID v4, time-ordered UUID v7 or ULID identifiers in bulk.

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Generate cryptographically random UUID v4, time-ordered UUID v7 or ULID identifiers in bulk.

Fine-tune

Optional — sensible defaults are already set.

Type

About UUID Generator

This generator creates UUID v4, UUID v7 or ULID identifiers in batches of up to 10,000, using the browser's cryptographic random number generator. Version 4 is fully random, while v7 and ULID start with a millisecond timestamp so they sort in creation order.

When it helps

  • Generating primary keys or seed data for a database or test fixtures.
  • Creating idempotency keys, correlation IDs or request IDs for API calls.
  • Producing time-sortable IDs (v7 or ULID) that keep B-tree indexes efficient for insert-heavy tables.

Tips

  • Prefer UUID v7 over v4 for database primary keys. Random v4 values insert at scattered positions in an index, while v7 values arrive in order.
  • Within one batch, each v7 or ULID value gets a timestamp one millisecond after the previous, so the list is strictly sortable.
  • ULIDs are 26 characters in Crockford Base32, shorter than the 36-character UUID text form, and avoid the letters I, L, O and U.
  • A v7 or ULID reveals roughly when it was created. Use v4 if that should not be exposed.

Good to know

Quick answers about uuid generator in your browser.

In theory yes, but a v4 UUID has 122 random bits, so the chance is negligible for any realistic number of IDs when a cryptographic random source is used, as it is here.

v4 is 122 bits of randomness with no meaning. v7, defined in RFC 9562, puts a 48-bit Unix millisecond timestamp first and fills the rest with random bits, so IDs sort by creation time.

Yes. UUID hex digits are case-insensitive when parsed, although RFC 9562 recommends lowercase output. Use the Uppercase option only if a system requires it.

Yes. There is no sign-up, no watermark and no limit on how many files you process.

No. Files are read and processed locally in your browser, so they never leave your device.

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Part of the Developer Utilities collection.