Generate one or many random UUID v4 identifiers, formatted the way you need — entirely in your browser. Nothing you generate here is ever sent to Brekzy.
A UUID (Universally Unique Identifier) is a 128-bit value used to identify something — a database record, a session, a file, an API request — without needing a central authority to hand out the next available number. It's written as 32 hexadecimal digits grouped into five sections separated by hyphens, like 550e8400-e29b-41d4-a716-446655440000. Because a UUID doesn't depend on a shared sequence or counter, two systems that have never communicated with each other can each generate their own UUIDs and still be extremely unlikely to collide.
UUID version 4 is the random variant of the UUID standard defined in RFC 4122. Instead of deriving the identifier from a timestamp, a MAC address, or a namespace — as some other UUID versions do — a v4 UUID is built almost entirely from random bits: 122 of its 128 bits are random, with the remaining 6 bits fixed to mark the version and variant. That randomness is what this tool generates.
Developers reach for UUIDs anywhere a unique identifier needs to exist without checking in with a central database first — primary keys in distributed databases, session and API tokens, request IDs for tracing logs across services, file names that need to avoid collisions, object identifiers in APIs, and test fixtures or seed data that shouldn't clash with real records.
A simple auto-incrementing ID (1, 2, 3...) is compact and easy to read, but it only makes sense within one database table, and it can leak information — like how many rows exist, or roughly how old a given row is — to anyone who sees it. A UUID trades that compactness for global uniqueness: it can be generated by any service, on any machine, without coordinating with anything else, and it doesn't expose a count or a creation order. Which one to use depends on the situation; an auto-incrementing ID is still a perfectly reasonable choice for a single, self-contained table.
In practice, yes, for any realistic use case. UUID v4 has 122 random bits, giving roughly 5.3 undecillion (5.3 × 1036) possible values. Generating billions of UUIDs would still leave the odds of ever seeing a duplicate vanishingly small. That said, "unique" here describes a statistical near-certainty, not a mathematical guarantee — because UUID v4 relies on randomness rather than a coordinated registry, a collision is not literally impossible, just improbable enough that it isn't a practical concern in real-world use.
A UUID v4 follows the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. Each x is a random hexadecimal digit. The 4 immediately after the second hyphen isn't random — it's fixed, and it's what marks this as a version 4 UUID. The y right after the third hyphen is the variant digit, and it's always one of 8, 9, a, or b, which identifies the UUID as following the standard variant layout. Everything else — the remaining 30 hex digits — is generated randomly, giving 32 hexadecimal digits plus 4 hyphens, for 36 characters in total.
A UUID (Universally Unique Identifier) is a 128-bit identifier, usually written as 32 hexadecimal digits in five hyphen-separated groups, used to label something uniquely without a central system assigning the next number in sequence.
UUID v4 is the random version of the UUID standard. 122 of its 128 bits come from a random number generator, with the remaining bits fixed to mark the UUID's version and variant. This tool generates UUID v4 only.
Statistically, yes. UUID v4 has 122 random bits, so the odds of two randomly generated UUIDs ever matching are astronomically small. It isn't a mathematical impossibility, since the values are random rather than centrally tracked, but in practice a collision isn't something you need to plan around.
Yes. Set "Number of UUIDs" to anywhere from 1 to 100, and a fresh batch generates automatically as you adjust it -- or click Generate UUIDs any time you want a new batch.
No. Every UUID this tool creates is generated in your browser using JavaScript. Nothing is sent to Brekzy or stored anywhere on our end.
Yes. They're valid, spec-compliant UUID v4 values suitable for development, testing, seed data, or any other situation where you need a unique identifier.
Not with this tool -- it generates UUID v4 only, which is the random, general-purpose version most developers reach for by default. Other UUID versions serve more specific purposes, such as deriving an ID from a timestamp or a name, and aren't implemented here.
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