A UUID v4 is a 128-bit identifier with 122 random bits, shown as 32 hexadecimal characters in five groups (8-4-4-4-12). The version digit is always 4 and the variant bits mark the RFC 4122 layout, so any v4 UUID is recognizable by its shape.

Can two generated UUIDs be the same?

Theoretically yes, but with 2^122 possible values the chance is astronomically small — you could generate billions per second for centuries without expecting a duplicate. For practical purposes every generated ID is unique.

Is this generator secure enough for tokens?

In modern browsers it uses crypto.randomUUID, which is cryptographically secure and suitable for session tokens and reset links. On very old browsers without Web Crypto it falls back to Math.random, which should only be used for non-security identifiers.

UUID vs auto-increment ID — which should I use?

Use UUIDs when records are created in distributed systems, offline clients, or merged databases where coordination is hard. Use auto-increment integers when you need compact storage, chronological ordering, or human-friendly references in a single database.

Free Online Tool

UUID Generator Tool

Generate bulk UUID v4 identifiers instantly with one-click copy. Create up to 50 unique IDs for databases, APIs and test data.

Reviewed by Prime Metric • Updated September 2026 WhatsApp

How many UUIDs? (1-50)

5 UUIDs

f47ac10b-58cc-4372-a567-0e02b2c3d479
550e8400-e29b-41d4-a716-446655440000
123e4567-e89b-42d3-a456-426614174000
6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b
c9bf9e57-1685-4c89-bafb-ff5af830be8a

About this Tool

The UUID Generator creates version 4 universally unique identifiers for databases, APIs, and distributed systems. Each ID is 128 bits of randomness, making collisions practically impossible across independent systems. IDs are generated entirely in your browser, so they are instant, free, and never leave your device.

Common Use Cases

Database Primary Keys

Generate collision-free primary keys for records created across multiple servers or offline clients that sync later without central coordination.

API Request Tracing

Attach a unique correlation ID to each API request so logs from different microservices can be tied together when debugging production issues.

Test Data Seeding

Bulk-generate dozens of realistic unique IDs to seed staging databases, populate fixtures, or load-test endpoints that require distinct identifiers.

File & Session Tokens

Create unguessable tokens for password resets, file uploads, or anonymous sessions where sequential numeric IDs would leak usage counts.

Pro Tips

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UUID v4 Is Random
Version 4 UUIDs are randomly generated with 122 bits of entropy. Never use them where sequential ordering matters — use auto-increment IDs or UUID v7 instead.
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Store as Native UUID Type
In Postgres use the uuid column type rather than text. It validates input, stores 16 bytes instead of 36 characters, and indexes faster.
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Don't Rely on Secrecy Alone
UUIDs are unguessable but not access control. Always verify permissions server-side even when resource URLs contain random identifiers.

FAQs

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