UUID Generator
Generate cryptographically random UUID v4 values instantly — single or bulk, entirely in your browser.
Frequently Asked Questions
What is a UUID?+
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 32 hexadecimal digits in five groups separated by hyphens: 8-4-4-4-12. The standard guarantees uniqueness across space and time without a central authority, making UUIDs ideal for database primary keys, distributed systems, and session identifiers.
What is UUID v4?+
UUID v4 is randomly generated. 122 of its 128 bits are random, with the remaining bits used to encode the version (4) and variant. The probability of generating two identical v4 UUIDs is astronomically small — approximately 1 in 5.3 × 10³⁶.
Is it safe to use UUIDs as database primary keys?+
Yes, but with a trade-off: v4 UUIDs are random, so they fragment B-tree indexes and can reduce insert performance at very high scale compared to sequential IDs. For most applications this is not a problem. If index performance matters, consider UUID v7 (time-ordered) or a ULID instead.
Are these UUIDs generated securely?+
Yes. This tool uses the browser's built-in crypto.randomUUID() API, which draws from the same cryptographically secure random number generator used for cryptographic operations — the same source as crypto.getRandomValues().
How to use
- Click Generate to create one or more UUID v4 values.
- Set the count to generate up to 100 UUIDs at once.
- Click any UUID to copy it, or use Copy All for bulk use.