UUID v4 Generator

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What Is a UUID v4?

A UUID v4 (Universally Unique Identifier, version 4) is a 128-bit identifier made from high-quality random numbers. It follows the RFC 4122 standard and is widely used for database keys, API request IDs, distributed systems, idempotency tokens, and file/object naming.

Because version 4 UUIDs rely on randomness instead of timestamps or MAC addresses, they avoid exposing system information and reduce the chance of collisions to an extremely low probability.

Secure Generation

All UUIDs come from crypto.getRandomValues(), giving you true random entropy required for compliant UUIDv4 generation.

RFC 4122 Compliant

Every UUID follows the exact layout: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where y can be 8, 9, a, or b.

Fully Local

No UUIDs are sent to any server. Everything runs in your browser for maximum privacy.

Common Use Cases for UUID v4

Database Primary Keys

UUIDs work well as uncoordinated primary keys in distributed databases. They reduce dependency on auto-increment sequences and avoid cross-system conflicts.

API Request Tracing

UUIDs make it much easier to track requests across microservices or distributed systems.

Idempotency Keys

Prevent duplicate charges, retries, or tasks by tagging requests with stable UUIDs.

File and Object Naming

Use UUIDs to create predictable, globally unique names for uploaded files or stored objects.

Frequently Asked Questions

Is this UUID generator RFC 4122 compliant?
Yes. Version and variant bits follow the exact RFC 4122 rules.
Are the UUIDs stored or logged?
No. Nothing leaves your browser. All generation happens locally.
Is a UUID v4 guaranteed unique?
Not mathematically guaranteed, but the chance of collision is so small that it's effectively zero for any real application.
Can I remove hyphens or change case?
Yes. Choose lowercase, uppercase, hyphenless, braces, or URN format in the generator options.