BullSwift

UUID Generator

Free online UUID v4 generator. Create unique identifiers instantly.

Click a button above to generate UUIDs

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What is a UUID Generator?

A UUID generator creates universally unique identifiers—128-bit values that are virtually guaranteed to be unique worldwide. Developers use UUIDs for database keys, session tokens, file names, and any scenario requiring collision-free identification without central coordination. Explore more Developer Tools.

Example

Text

Click 'Generate 1' button

Result

550e8400-e29b-41d4-a716-446655440000

Explanation

Each UUID v4 is randomly generated with 122 bits of randomness, making collisions statistically impossible in practical use.

How This Tool Works

Click a generate button to create UUIDs. The tool uses your browser's cryptographically secure random number generator to produce unique identifiers. Each UUID is virtually guaranteed to be unique worldwide.

1

Input

Click a button to generate 1, 5, 10, 25, or 50 UUIDs at once.

2

Processing

The browser generates 122 random bits using crypto.randomUUID().

3

Output

Unique 36-character identifiers in standard 8-4-4-4-12 format.

When Developers Use UUIDs

UUIDs solve identification problems across many development scenarios.

Database Keys

Primary keys that work across distributed databases without conflicts.

Session Tokens

Unique session identifiers for user authentication and tracking.

File Naming

Guaranteed unique filenames for uploads and generated content.

API Resources

Stable, unique identifiers for REST API resources and entities.

UUID v4 vs Other Identifiers

UUID v4

  • Globally unique without coordination
  • Works offline and in distributed systems
  • No sequential patterns to exploit
  • Standardized 36-character format

Auto-Increment IDs

  • Requires central database authority
  • Sequential and predictable
  • Reveals record count and order
  • Compact integer format

When to Use This Tool

  • •When creating database records that need globally unique identifiers without relying on sequential auto-increment IDs.
  • •When designing APIs with resource identifiers that remain stable across different environments.
  • •When generating session tokens, correlation IDs in distributed systems, or unique file names.

Common Mistakes

  • •

    Using UUIDs as passwords or secrets

    UUIDs are identifiers, not secrets. They can be exposed publicly without security risk.

  • •

    Assuming UUIDs are sequential

    UUID v4 is random with no ordering. Use timestamps or sequences if you need order.

  • •

    Storing UUIDs inefficiently

    Store as binary (16 bytes) in databases instead of strings (36 characters) for better performance.

Learn More About Developer Tools

Explore related tools and guides for developers.

Frequently Asked Questions

Common questions about this tool answered.

A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across all devices and time. It's formatted as a 36-character string with hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). UUIDs are used to identify information without relying on a central authority.
UUID v4 is a randomly generated UUID. It uses random or pseudo-random numbers for all bits except the version (4) and variant indicators. This makes v4 UUIDs statistically unique without requiring any coordination or central registry.
UUID v4 has 122 random bits, resulting in approximately 5.3 x 10^36 possible values. The probability of generating a duplicate is astronomically low—you would need to generate billions of UUIDs per second for decades to have a meaningful chance of collision.
UUID v4 generated using crypto.randomUUID() uses cryptographically secure random numbers, making them suitable for security-sensitive applications. However, they are identifiers, not secrets—they can be exposed publicly without compromising security.
Use UUIDs when you need unique identifiers without a central database, for database primary keys in distributed systems, for session IDs, for file names that must be unique, or for any scenario where collision-free identification is required.

Why Choose BullSwift UUID Generator?

Compare BullSwift to other online tools and see why writers prefer us.

FeatureBullSwiftOthers
100% FreeOften limited
No Account RequiredSign-up walls
No AdsAd-heavy
Fast ResultsSlow processing
Privacy FirstData collection

All BullSwift tools run entirely in your browser. Your text is never sent to our servers.

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