UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across space and time. It's commonly used as primary keys in databases.

Is UUID v4 truly random?

Yes, UUID v4 uses cryptographically secure random numbers. The probability of generating duplicate UUIDs is astronomically low (1 in 2^122).

Free UUID Generator Online 2026

Q: What is the difference between UUID and GUID?

UUID and GUID are essentially the same thing. GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID standard. Both follow the same format.

Welcome to Code Formatter's UUID Generator � the most powerful and secure tool for generating Universally Unique Identifiers (UUIDs) and Globally Unique Identifiers (GUIDs). Whether you're a backend developer creating database primary keys, a DevOps engineer generating deployment tokens, or a frontend developer mocking API responses, our tool delivers cryptographically secure UUIDs instantly.

UUIDs have become the backbone of distributed systems. Unlike auto-incrementing integers, UUIDs can be generated independently on any machine without coordination, making them perfect for microservices architectures, multi-database synchronization, and offline-first applications. Our online UUID generator supports UUID v1, v4, bulk generation, and multiple output formats � all processed securely in your browser.

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE). The standard format consists of 32 hexadecimal digits displayed in five groups separated by hyphens:

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

Where M indicates the UUID version (1-5) and N indicates the variant. The total possible combinations are 2^122 (approximately 5.3�10^36), making collisions virtually impossible.

UUID Versions Explained

UUID v1 (Timestamp-based)

UUID v1 combines the current timestamp with the MAC address of the generating machine. This creates UUIDs that are sortable by creation time but may expose information about when and where they were generated. Best for scenarios requiring temporal ordering.

UUID v4 (Random)

UUID v4 is generated using cryptographically secure random numbers. This is the most widely used version because it offers the strongest uniqueness guarantees without revealing any information about the generation source. Our generator uses the browser's crypto.getRandomValues() API for maximum security.

How to Generate UUIDs

Select your preferred UUID version (v4 recommended for most cases)
Choose the output format (lowercase, uppercase, with braces, or without hyphens)
Enter the quantity of UUIDs you need (1 to 1000)
Select the separator format (new line, comma, or JSON array)
Click GENERATE and copy your UUIDs instantly

Key Features

Cryptographically Secure: Uses the Web Crypto API for true randomness
Bulk Generation: Generate up to 1000 UUIDs in a single click
Multiple Formats: Lowercase, uppercase, with braces, without hyphens
Export Options: Copy to clipboard or download as .txt file
JSON Array Output: Perfect for pasting directly into code
100% Client-Side: Your UUIDs never leave your browser
Offline Support: Works without internet after page load

Common Use Cases

1. Database Primary Keys

UUIDs are ideal for distributed databases where multiple nodes need to generate unique IDs independently. Unlike sequential integers, UUIDs prevent key collisions during data merges and replication.

2. API Request Idempotency

Include a UUID in API requests to ensure the same operation isn't processed twice. Payment gateways and financial applications rely heavily on this pattern.

3. Session Tokens

Generate secure session identifiers that are impossible to guess or enumerate, protecting your application from session hijacking attacks.

4. File Naming

Avoid filename collisions when storing user uploads by prefixing or replacing filenames with UUIDs.

UUID vs GUID: What's the Difference?

Technically, UUID and GUID are the same thing. GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID specification. Both follow RFC 4122 and produce identical formats. The terms are used interchangeably in the industry.

Frequently Asked Questions

Are UUIDs truly unique?

Yes. UUID v4 has 2^122 possible values. The probability of generating two identical UUIDs is approximately 1 in 2.71 quintillion. You're more likely to be struck by lightning while winning the lottery than generating a duplicate UUID.

Can I use UUIDs as database primary keys?

Absolutely. UUIDs are excellent for distributed systems. However, they use more storage (16 bytes vs 4 bytes for INT) and may impact index performance. Consider UUIDv7 for sortable timestamps if ordering matters.

Is this tool secure for generating tokens?

Yes. We use the Web Crypto API's crypto.getRandomValues() which provides cryptographically secure random numbers suitable for security-sensitive applications.

Why use UUID v4 over v1?

UUID v4 is purely random and doesn't expose any information about generation time or machine. UUID v1 includes timestamp and MAC address data, which may be a privacy concern in some applications.

Can I generate UUIDs offline?

Yes! Once this page loads, it works entirely offline. All UUID generation happens in your browser using JavaScript.

What's the maximum number I can generate?

Our tool supports up to 1000 UUIDs per generation. For larger batches, simply click Generate multiple times.

Code Formatter � 2026. Professional developer tools built with privacy and performance in mind.

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