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UUID Generator (v4)

Generate cryptographically random UUIDs (v4) in bulk. Multiple format options, copy + clear.

Utility

UUID Generator (v4)

Generated on April 25, 2026

Sample format: 550e8400-e29b-41d4-a716-446655440000(36 chars)
Click Regenerate to create UUIDs.
UUID v4: 122 bits of randomness from crypto.getRandomValues. Collision probability is so low it's commonly described as "practically impossible" — you'd need to generate ~2.7 quintillion UUIDs to have a 50% chance of a single collision.

?What is the UUID Generator (v4)?

The UUID Generator produces version-4 (random) UUIDs — 128-bit identifiers with 122 bits of cryptographic randomness from your browser's crypto.getRandomValues. UUIDs are the standard way to assign globally-unique IDs to database rows, file uploads, session tokens, distributed-system events, and anything else that needs a collision-resistant identifier without a central authority. Generate up to 1,000 at a time and export as lowercase, UPPERCASE, no-hyphens (compact), or {braced} format depending on your platform's convention. All generation happens in your browser — these UUIDs are unique to your session and never logged or stored.

The Formula

UUID v4: 128 bits = 32 hex chars in 8-4-4-4-12 grouping. Version (4) is hard-coded in the 13th hex digit; variant (10xx) in the 17th. Remaining 122 bits are random.

Practical Examples

1

Database primary keys: `INSERT INTO users (id, …) VALUES ('550e8400-e29b-41d4-a716-446655440000', …)`.

2

Idempotency keys for HTTP requests: `Idempotency-Key: <uuid>` to prevent duplicate processing.

3

Distributed event IDs: every event gets a UUID so consumers can deduplicate and trace.

4

Session tokens, file upload IDs, correlation IDs in microservice tracing.

5

Bulk-generate test data: 1000 user IDs for fixtures or load tests.

Frequently Asked Questions

Effectively yes. With 122 random bits per v4 UUID, you'd need to generate ~2.7 quintillion (2.7 × 10^18) UUIDs to have a 50% chance of one collision (birthday-paradox math). For practical purposes, treat them as unique.

Popular Conversions

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