UUID v4 (Universally Unique Identifier version 4) is a random UUID generated using cryptographically secure random numbers. It consists of 32 hexadecimal digits displayed in 5 groups separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). The probability of duplicates is extremely low (negligible for practical purposes).

Are generated UUIDs truly unique?

UUID v4 uses cryptographically secure random generation, making the probability of duplicates extremely low (approximately 1 in 5.3 × 10^36 for a single UUID). For practical purposes, UUIDs can be considered unique. However, there's no central registry—uniqueness is probabilistic, not guaranteed.

Can I generate UUIDs offline?

Yes! Once the page is loaded, UUID generation works offline. All generation happens in your browser using the Web Crypto API—no internet connection is required after initial page load. This makes it perfect for offline development or when working without internet access.

What's the difference between UUID v4 and other versions?

UUID v4 is random (uses cryptographically secure random numbers). UUID v1 is based on MAC address and timestamp. UUID v3 and v5 are based on names and namespaces (MD5 and SHA-1 hashing). This tool only generates v4 UUIDs, which are the most common for applications.

Can I use these UUIDs in production?

Yes! UUID v4 UUIDs generated by this tool are suitable for production use. They use cryptographically secure random generation (Web Crypto API), making them appropriate for database keys, API identifiers, and any production use case requiring unique identifiers.

UUID Generator - Generate UUIDs Free

When to Use This Tool

Use this when:

You're developing applications and need unique identifiers for database records or entities
You're working with APIs and need to generate unique IDs for requests or resources
You're building distributed systems and need globally unique identifiers
You need session IDs, transaction IDs, or other unique identifiers for your application
You're testing applications and need sample UUIDs for test data
You want to generate multiple UUIDs at once for bulk operations
You need cryptographically secure random identifiers (UUID v4 uses secure random generation)

Don't use this if:

You need UUIDs with specific versions other than v4 (this tool only generates v4 UUIDs)
You require UUIDs based on MAC addresses or timestamps (v4 UUIDs are random, not based on hardware/time)
You need to generate UUIDs in a specific format or encoding (this tool generates standard UUID format)
You require UUID validation or parsing (this tool only generates, doesn't validate)
You need UUIDs for offline use without browser access (use command-line tools instead)

What is a UUID Generator?

A UUID (Universally Unique Identifier) generator creates unique 128-bit identifiers in various formats — UUID v4 (random), UUID v1 (time-based), and GUID format. Our generator runs entirely in your browser using the Web Crypto API for cryptographic randomness.

UUIDs are fundamental building blocks in software development: they serve as primary keys in databases, unique identifiers for distributed systems, correlation IDs for log tracing, session identifiers, and unique file names. Their guaranteed uniqueness without central coordination makes them essential for microservice architectures and distributed computing.

This tool is valuable for software developers needing unique identifiers for database records, architects designing distributed systems, API developers generating request IDs, testers creating test data with unique keys, and anyone who needs guaranteed-unique identifiers without a database sequence.

Compared to using language-specific UUID libraries (require development environment), online generators that may track generated UUIDs, or database-generated sequences (require database access), PureXio generates cryptographically random UUIDs instantly in your browser.

The tool generates standard UUID v4 (random) identifiers using the Web Crypto API for true randomness, supports bulk generation (create 1–1000 UUIDs at once), offers multiple output formats (standard, no dashes, uppercase, braces for GUID), and includes a UUID validator to check existing identifiers. Each UUID has a probability of duplication so low (1 in 2^122) that it's effectively zero.

Best for: generating UUID v4, v1, and GUID identifiers. Bulk generation, multiple formats, UUID validation. Cryptographically random. Fully private.

How to Generate UUIDs

Set the number of UUIDs you want to generate (1-50). Use the slider or input field to specify count

Click 'Generate UUID(s)' to create random v4 UUIDs. UUIDs appear instantly in the results

Copy individual UUIDs or copy all UUIDs at once. Use for database keys, API identifiers, or any unique ID needs

Common Use Cases

Generate unique IDs for database records (primary keys, foreign keys)

Create unique identifiers for API resources or endpoints

Generate session IDs or transaction IDs for web applications

Create unique identifiers for distributed systems or microservices

Generate test data with unique IDs for application testing

Create unique identifiers for file uploads or user-generated content

Generate unique codes for tracking, analytics, or logging purposes

Features

Generate random v4 UUIDs (Universally Unique Identifiers) instantly

Generate single UUID or multiple UUIDs (up to 50 at once)

Cryptographically secure random generation using Web Crypto API

Standard UUID format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

One-click copy for individual UUIDs or all UUIDs at once

100% private—all generation happens locally in your browser

No server requests—UUIDs are generated client-side

Limitations & Constraints

Only generates UUID v4 (random UUIDs)—doesn't support other UUID versions (v1, v3, v5)

Maximum 50 UUIDs can be generated at once—for more, generate in multiple batches

UUIDs are random—no guarantee of uniqueness across different browser sessions (though collision probability is negligible)

Requires browser with Web Crypto API support (modern browsers only)

UUIDs are generated locally—not registered or tracked in any central system

Troubleshooting

UUID generation fails or shows error

Solution: Ensure you're using a modern browser with Web Crypto API support (Chrome, Firefox, Safari, Edge). Older browsers may not support UUID generation. Try refreshing the page or using a different browser. The tool requires crypto.randomUUID() or crypto.getRandomValues() support. Prevention: Use modern browsers (Chrome 92+, Firefox 95+, Safari 15.4+, Edge 92+).

Need more than 50 UUIDs

Solution: Generate UUIDs in batches—generate 50, copy them, then generate another batch. The limit of 50 is to prevent browser performance issues. For very large quantities, generate multiple batches or use command-line tools. Prevention: Generate UUIDs in batches if you need many at once.

UUID format looks wrong or invalid

Solution: UUIDs should be in format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx (32 hex digits with hyphens). If format looks wrong, check that you copied the complete UUID. The tool generates standard UUID v4 format. If UUIDs appear invalid, try generating new ones. Prevention: Ensure you copy complete UUIDs including all hyphens.

Need UUIDs with specific characteristics

Solution: This tool generates random v4 UUIDs only. If you need UUIDs based on names (v3, v5) or timestamps (v1), use specialized UUID tools or libraries. For most use cases, random v4 UUIDs are sufficient. Prevention: Understand that this tool generates random v4 UUIDs—use other tools for different UUID versions.

Want to validate or parse existing UUIDs

Solution: This tool only generates UUIDs—it doesn't validate or parse existing UUIDs. For validation, use UUID validation tools or libraries. The tool is designed for generation only. Prevention: Use UUID validation tools separately if you need to check UUID validity.