Practical example
Generate a batch for test records, but keep the canonical lowercase form with hyphens if the database column uses a native UUID type.
UUID Generator
Generate one or many UUID v4 values instantly with options for uppercase output and no dashes.
Options
Generated UUIDs
0 generatedWhat is a UUID generator?
A UUID generator creates universally unique identifiers that are commonly used in databases, APIs, distributed systems, and testing.
UUID v4 values are random and are often used when you need identifiers that are extremely unlikely to collide.
How to use the UUID Generator
- Choose how many UUIDs you want to generate.
- Optionally enable uppercase or remove dashes.
- Click Generate.
- Copy the result and use it in your app, fixtures, or database.
Tips
- UUID v4 is useful for IDs in distributed systems.
- Bulk generation helps with test data and imports.
- Removing dashes can be useful for systems that require compact IDs.
- Uppercase output is mostly a formatting preference unless your system requires it.
UUID usage checks
Database identifiers
UUIDs work well for distributed inserts, public IDs, fixtures, and records created outside a single database sequence.
Public versus private IDs
A UUID is hard to guess, but it is not an authorization control. Always check permissions for resources addressed by UUID.
Dash formatting
Keep dashes when possible because many libraries and database types expect canonical UUID formatting.
Test data batches
Bulk generation is useful for seed data and tests, but keep generated examples separate from production identifiers.
Related guides
Learn the workflow behind this tool and what to check next.
UUID checks before using generated identifiers
UUIDs are useful distributed identifiers, but their version, storage format, privacy properties, and database behavior still matter.
Choose the version
Use random UUID v4 for general uniqueness; consider time-ordered formats only when the application and database explicitly support them.
Canonical format
Store and compare identifiers consistently with lowercase or uppercase, hyphens, braces, and database-native UUID types.
Not a secret
Do not treat an unguessable-looking UUID as authorization; validate access separately for every referenced resource.
Index behavior
Review index size, insertion locality, query patterns, and migration compatibility before replacing sequential database keys.
A practical example, an edge case, and a maintainer note
Edge case
A UUID is difficult to guess but is not an access-control check. An API must still verify that the current user owns the referenced resource.
Maintainer note
Use UUIDs as identifiers, not passwords or session secrets; their job is uniqueness, not authentication.
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UUID Generator FAQ
Are generated UUIDs sent to the server?
No. UUIDs are generated by your browser's crypto.getRandomValues — the server never sees them, so they are safe to use in private systems.
Can I generate multiple UUIDs at once?
Yes. You can generate one or many UUIDs in a single click.
Is UUID v4 random?
Yes. UUID v4 is based on random values and is commonly used for unique identifiers.