RFC 9562 · Web Crypto · no upload

Generate UUIDs and inspect what every field actually proves

Create bounded UUIDv4 or UUIDv7 batches in your browser, choose an exact text format, and strictly validate canonical UUIDs without repair. See the version, variant, bytes and UUIDv7 time while keeping identifiers local.

Open UUIDLens

No account · no API · 1–1,000 values

Three explicit steps

Choose, run, inspect

01

Choose the UUID contract

Set version, format and bounded count.

02

Generate or validate locally

Web Crypto and strict parsing run here.

03

Review field evidence

Copy only after checking the receiving contract.

Practical identifier work

Useful for fixtures, migrations, API examples and local validation

  • Generate random UUIDv4 fixture values.
  • Create time-ordered UUIDv7 sample IDs.
  • Format the same bits as GUID text.
  • Reject noncanonical input before reuse.

Reviewed vectors

Reproduce valid and invalid UUID cases

Choose UUIDv4 or UUIDv7, a bounded batch and an explicit format. Validation accepts one exact canonical lowercase UUID. Identifiers, random bytes and timestamps never leave this browser.
View examples

RFC 9562 · local Web Crypto

Generate or validate exact UUID text

Choose UUIDv4 or UUIDv7, a bounded batch and an explicit format. Validation accepts one exact canonical lowercase UUID. Identifiers, random bytes and timestamps never leave this browser.

Open UUIDLens