UUID Generator
Generate universally unique identifiers (UUID v4) using the Web Crypto API — random and cryptographically secure.
What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID in the
Microsoft world, is a 128-bit identifier designed to be unique in space and time
without needing a central authority. It is represented by 32 hexadecimal digits
grouped into five blocks separated by hyphens, in the format 8-4-4-4-12 —
for example, 3f2504e0-4f89-41d3-9a0c-0305e82c3301.
UUIDs are widely used as database primary keys, API resource identifiers, temporary file names and idempotency keys — situations where generating unique IDs in a distributed way (across multiple servers, without coordination) is essential.
What is UUID v4?
Version 4 is the most common: almost all of its bits are random. This
tool uses crypto.randomUUID() when available — or, as a fallback,
crypto.getRandomValues() — both cryptographically secure generators from
the Web Crypto API. This guarantees high-quality randomness, without the
predictability of Math.random().
With 122 effectively random bits, the probability of collision (two identical UUIDs) is astronomically low — in practice, negligible even when generating billions of identifiers.
Options in this tool
- Quantity: generate from 1 to 100 UUIDs at once.
- With/without hyphens: some systems prefer the "raw" UUID, without separators.
- Uppercase/lowercase: the default is lowercase, but some environments (e.g., GUID in .NET) display it in uppercase.
- Copy: copy a single UUID or all at once (one per line).
Frequently Asked Questions (FAQ)
Can I use these UUIDs in production?
Yes. They are valid UUID v4s, generated by a cryptographically secure generator. They are suitable for database keys, API identifiers and the like.
Can two UUIDs come out the same?
In theory yes, but the probability is so low it is considered negligible in practice. It would take billions of generated UUIDs for the chance of collision to become even minimally relevant.
What's the difference between UUID and GUID?
They are essentially the same thing. GUID (Globally Unique Identifier) is the name used by Microsoft; UUID is the RFC standard term. The 128-bit format is identical.