A UUID (Universally Unique Identifier) is a 128-bit identifier used to uniquely identify information in computer systems. UUIDs are standardized by RFC 4122 and are commonly used in databases, distributed systems, and software development.

UUID v4 is generated using random numbers. It provides 122 bits of randomness, making collisions extremely unlikely (about 1 in 5.3 x 10^36).

Are the generated UUIDs secure?

Yes, UUIDs are generated using the Web Crypto API which provides cryptographically secure random values. All generation happens locally in your browser.

UUID Generator (RFC 4122)

No dashes UPPERCASE

UUID Tools

UUID Validator

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UUID Decoder

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What is a UUID?

A UUID (Universally Unique Identifier), also known as GUID (Globally Unique Identifier), is a 128-bit value used in software systems to uniquely identify an object, record, request or transaction. UUIDs follow the RFC 4122 standard and are represented as 36-character strings in the format 8-4-4-4-12, for example: 550e8400-e29b-41d4-a716-446655440000.

What is UUID v4?

UUID version 4 is the most widely used variant. It is generated using cryptographically secure random numbers and guarantees extremely low collision probability (1 in 2^122), making it ideal for database primary keys, distributed systems, REST APIs, session identifiers, microservices and transaction IDs.

About this Free UUID Generator

This online UUID generator creates RFC 4122 compliant UUID v4 and v1 values instantly, directly in your browser, without sending any data to external servers. Generate random UUIDs, bulk UUIDs, or timestamp-based UUIDs with format options like uppercase or no dashes. Perfect for developers building Node.js, Python, Java, Go, or JavaScript applications.

Frequently Asked Questions

Is this UUID Generator RFC 4122 compliant?

Yes. The generator produces version 4 UUIDs that follow the RFC 4122 specification using the browser's cryptographically secure crypto.randomUUID() API.

Are the generated UUIDs unique?

Version 4 UUIDs contain 122 random bits, resulting in 2^122 possible combinations. The probability of collision is effectively zero for practical use.

Does this tool store my data?

No. Everything is generated in your browser using crypto.randomUUID(). No data is transmitted or saved on servers. History is stored locally in your browser only.

What is the difference between UUID v1 and v4?

UUID v1 uses timestamp and MAC address information, while UUID v4 relies purely on randomness and is therefore safer and more commonly used in modern applications.