UUID / GUID Generator
Generate random UUID v4 identifiers. Cryptographically secure, in bulk, with formatting options — runs entirely in your browser.
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What is a UUID?
A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier) in Microsoft's ecosystem, is a 128-bit value used to identify an object with high uniqueness without coordinating with a central authority. UUIDs are written as 32 hexadecimal digits split by hyphens into five groups: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx. The M position encodes the version; N encodes a variant bit.
UUID v4 (what this tool generates)
Version 4 UUIDs use 122 bits of cryptographically secure randomness plus 6 fixed bits (4 for version, 2 for variant). With 2¹²² possible values, the probability of any two generated UUIDs colliding is astronomically low — for most workloads it's safe to treat them as permanently unique.
How to use
- Pick how many UUIDs you want (1–10000).
- Toggle uppercase / no-hyphens / curly braces if your target system needs a specific format.
- Click Generate. Click Copy or Download to export.
- Click Nil UUID for the all-zero placeholder
00000000-0000-0000-0000-000000000000.
When to use UUIDs
- Primary keys in distributed databases — no central sequence needed.
- Session & API tokens — unpredictable identifiers.
- File names to prevent collisions when multiple processes write to the same bucket.
- Correlation IDs for tracing requests across microservices.
- Device identifiers in IoT fleets.
Privacy
Generation is local. Nothing is sent to any server. The browser's native crypto.randomUUID() is used where available, falling back to crypto.getRandomValues().