UUID Generator
Generate one or many UUID v4-style identifiers in your browser for development, testing, APIs, and distributed records.
Generate UUIDs when you need identifiers that can be created independently without asking a central database for the next number. Random UUIDs are useful for API objects, offline-created records, imports, events, and distributed systems. A UUID can make an identifier difficult to guess, but it is not an authorization system—applications still need proper access checks around private data.
Generate UUID v4 identifiers in your browser
UUIDs are 128-bit identifiers commonly written as hexadecimal groups, for example 550e8400-e29b-41d4-a716-446655440000. Version 4 UUIDs use random bits so independent systems can create identifiers without coordinating a central sequence.
Why UUIDs are useful
A database can generate numeric IDs such as 1, 2, 3, but those sequences can collide when records are created independently in multiple systems. UUIDs make collision extremely unlikely and are therefore common in distributed applications, imports, APIs, and offline-first systems.
UUIDs are identifiers, not secrets
Do not assume a UUID is private just because it looks random. If possession of an identifier grants access to private data, the application still needs proper authentication and authorization.
Trade-offs compared with sequential IDs
UUIDs are longer and less pleasant for humans to read aloud or type. Random UUIDs can also have database-indexing implications compared with compact sequential keys. Choose an identifier format that fits the system rather than using UUIDs automatically everywhere.
Frequently asked questions
Can two UUID v4 values ever be the same?
A collision is theoretically possible, but with a proper random generator the probability is extremely small for ordinary application use.
Should UUIDs be uppercase or lowercase?
The hexadecimal digits are commonly displayed lowercase, but the textual case does not change the underlying identifier value.