UUID Generator

Generate UUID v4 values instantly. Single or bulk. All generation happens in your browser — nothing is sent to a server.

UUID v4
Bulk Generation
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What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit label used to identify information in computer systems. The standard format is 32 hexadecimal digits displayed in five groups separated by hyphens:

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

UUID v4 is the most widely used version. All 122 variable bits are randomly generated, making collisions statistically impossible in practice. It is used for database primary keys, session tokens, file names, and distributed system IDs.

UUID v4 vs other versions

  • v1 — Based on timestamp + MAC address. Predictable, not recommended for security-sensitive IDs.
  • v3 / v5 — Deterministic, namespace-based (MD5 or SHA-1). Used when you need the same ID for the same input.
  • v4 — Randomly generated. The default choice for database keys and unique tokens.
  • v7 — Timestamp-sortable random UUID. Increasingly used in databases for index efficiency.

Use cases

  • Database primary keys (PostgreSQL uuid type, MongoDB ObjectId alternative)
  • REST API resource identifiers (/users/550e8400-e29b-41d4-a716-446655440000)
  • Session and token IDs
  • Idempotency keys for payment APIs
  • File names for uploaded assets

Frequently Asked Questions

What is a UUID v4?

UUID v4 is a randomly generated 128-bit identifier formatted as five hyphen-separated groups of hexadecimal characters (e.g. 550e8400-e29b-41d4-a716-446655440000). It is the most commonly used UUID version for generating unique IDs without a central registry.

Are the generated UUIDs truly unique?

Yes. This tool uses crypto.randomUUID(), which relies on the browser's cryptographically secure random number generator. The theoretical chance of generating two identical UUID v4 values is approximately 1 in 5.3 × 10³⁶ — effectively zero in any practical scenario.

Is my data sent to a server?

No. UUID generation happens entirely in your browser using the native crypto.randomUUID() API. Nothing is transmitted to any server.

What is the difference between UUID and GUID?

GUID (Globally Unique Identifier) is Microsoft's name for the same concept. UUID and GUID refer to the same 128-bit identifier format defined by RFC 4122. The terms are interchangeable in practice.

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