What UUIDs are good for
A UUID is a 128-bit identifier written as a standardized string such as550e8400-e29b-41d4-a716-446655440000. Developers use UUIDs when they need identifiers that can be created independently across machines without asking a central database for the next number.
This generator uses UUID v4, the random variant. It is useful for local fixtures, demo records, tests, seed data, correlation IDs, and object keys where ordering is not important.
When not to use a random UUID
- When your database needs mostly ordered primary keys for write performance.
- When IDs must be short enough for people to read aloud or type manually.
- When the identifier should encode creation time or shard information.
- When you need cryptographic secrets; UUIDs are identifiers, not passwords or tokens.
Frequently asked questions
What version of UUID does this generate?
This tool generates UUID v4 values using the browser's crypto.randomUUID API. UUID v4 identifiers are random rather than time-based.
Are UUIDs guaranteed to be unique?
No random identifier is mathematically guaranteed, but UUID v4 has such a large random space that collisions are extraordinarily unlikely for normal application use.
Can I use these IDs in production?
They are suitable for many production identifiers, but choose an ID strategy that matches your database, indexing, ordering, and security requirements.
Are generated IDs sent anywhere?
No. The IDs are generated locally by your browser and are not uploaded, stored, or logged by this site.
Related tools
- UUID v4 Guide for when random identifiers are the right choice and when they are not.
- JSON Formatter for turning generated IDs into fixture payloads.
- Case Converter for naming fixture keys consistently.