UUID Generator
Generate UUIDs online instantly. Supports v1/v4/v7, bulk generation, and validation. Essential developer tool.
About This Tool
UUID Generator creates universally unique identifiers (UUIDs) conforming to RFC 4122 version 4. It can generate single or bulk UUIDs with options for uppercase/lowercase and with or without hyphens. Widely used by developers for database primary keys, distributed system identifiers, session tokens, and correlation IDs.
How It Works
A UUID (Universally Unique Identifier) is a 128-bit value represented as 32 hexadecimal digits in the format 8-4-4-4-12 (e.g., 550e8400-e29b-41d4-a716-446655440000). Version 4 UUIDs are generated entirely from random or pseudo-random numbers, with two fixed bits: the version field (4 bits set to 0100) and the variant field (2 bits set to 10).
This tool uses `crypto.getRandomValues()` to fill a 16-byte array with cryptographically secure random values. It then sets the version nibble (bits 48-51) to 0x4 and the variant bits (bits 64-65) to binary 10. The resulting 128 bits are formatted as a hexadecimal string with hyphens. The probability of generating a duplicate is astronomically low — with 122 random bits, you would need to generate approximately 2.71 x 10^18 UUIDs to have a 50% chance of a single collision (the birthday paradox bound).
How to Use
- Select a UUID version (v4 random / v7 time-ordered / v1 timestamp).
- Choose how many to generate (1-100).
- Set format options (remove hyphens, uppercase).
- Click Generate UUID. Single generation auto-copies to clipboard.
- For bulk generation, use Copy All to copy all at once.
- Use the Validate tab to check UUID validity and version.