zippydevtoolsChoose UUID v4 for independent test identifiers
UUID v4 is a practical choice when fixtures, mocks, or distributed components need identifiers without coordinating a central numeric sequence.
The random identifier carries no business meaning or creation order. Keep a database uniqueness constraint even though collisions are extremely unlikely in ordinary fixture-sized batches.
Copy-ready fixture formats
Choose lines to paste values into separate fields. A three-value result follows this structure: 40cbdcf1-e92d-4f82-850f-08d761f5fe31, then one UUID on each following line.
Choose JSON for an array such as ["40cbdcf1-e92d-4f82-850f-08d761f5fe31", "da87d90f-2a47-4e1e-bb8e-8cc436f860ba"]. Choose CSV for a uuid header followed by one value per row.
The copy button preserves the displayed format, so the output can move directly into a fixture before validation with the JSON Formatter or the target test suite.
Understand collision risk and batch size
A UUID v4 includes 122 random bits after version and variant fields. That makes accidental duplicates very unlikely for normal application and test volumes, but it is not a mathematical guarantee.
The online tool limits each run to 20 values so a manual batch stays readable and reviewable. Generate larger volumes in application code or the database, where uniqueness checks and failure handling belong.
When to choose another identifier
Choose a sortable identifier strategy when indexes or reports depend on creation order, and choose a deterministic identifier when the same input must always produce the same value.
Do not expose UUID v4 as a password, API key, session token, or authorization proof. Use a credential-specific generator and storage policy for secrets; use hashes only when the workflow needs content fingerprints.