Developer Tool
UUID Generator
Generate v1, v4, v5 or v7 UUIDs instantly in your browser. No data sent to any server.
Namespace UUID
Name
UUIDs
Click Generate…
What is a UUID?
Definition
A UUID (Universally Unique Identifier) is a 128-bit RFC 4122 standardized identifier written as 32 hex digits separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
v4 — Random
The most widely used version. Generates 122 random bits. Collision probability is astronomically low — 1 in 5.3 × 10³⁶. Ideal for database IDs.
v7 — Time-ordered
New standard (RFC 9562). Starts with a Unix timestamp in milliseconds, ensuring natural chronological sort order in databases. Recommended for new applications.
v5 — Namespace/Name
Generates a deterministic UUID via SHA-1 from a namespace and name. The same namespace/name pair always produces the same UUID. Useful for URLs, emails, or stable resources.
FAQ
UUID vs GUID — what is the difference?
GUID (Globally Unique Identifier) is Microsoft's term for the same concept. They are technically identical — a 128-bit identifier formatted the same way.
Are these UUIDs cryptographically secure?
UUID v4 uses crypto.getRandomValues() — the browser's cryptographically secure random number generator. v1 and v7 use timestamps which are not secret. Never use UUIDs as security tokens.
Is my data sent to a server?
No. All UUID generation happens 100% in your browser using native JavaScript APIs. Nothing is ever transmitted.
Can two generated UUIDs ever be identical?
In theory yes, in practice no. For v4, you would need to generate approximately 2.7 quintillion UUIDs before having a 50% chance of a single collision.