Generate UUID v4 identifiers. Bulk generation up to 20. Everything runs in your browser.
Click Generate to create UUID(s)
Set the count (1–20), toggle Uppercase or No dashes if needed, then click Generate. The tool calls crypto.randomUUID() once per UUID — the browser's native cryptographically secure UUID v4 generator. Click Copy next to any individual UUID to copy just that one, or click Copy All to copy the full list as newline-separated values. Nothing is sent to any server.
A UUID is a 128-bit identifier formatted as 32 hex digits in 8-4-4-4-12 groups separated by hyphens. Version 4 UUIDs are randomly generated and have a collision probability so low that practical uniqueness is guaranteed across distributed systems.
GUID is Microsoft's name for the same standard. They are technically identical — 'UUID' is the IETF term (RFC 4122) used in most languages, while 'GUID' is the Microsoft term used in .NET and COM.
It is a native browser API (and Node.js 14.17+) that generates a Version 4 UUID using the OS cryptographic entropy source. It contains 122 bits of random data — 6 bits are reserved for version and variant fields.
UUIDs work well in distributed systems because they can be generated client-side. The tradeoff is that random v4 UUIDs fragment B-tree indexes over time. UUID v7 (time-ordered) or ULID are better choices if write performance is critical.
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