UUID Generator
Generate random v4 UUIDs instantly. Everything runs in your browser — nothing is sent to a server.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is practically guaranteed to be unique across all devices and time. UUIDs are formatted as 32 hexadecimal digits displayed in five groups separated by hyphens, like 550e8400-e29b-41d4-a716-446655440000. They are used in databases, distributed systems, and anywhere a unique identifier is needed without a central authority.
What is UUID v4?
UUID version 4 is generated using random or pseudo-random numbers. Six bits are fixed (four for the version and two for the variant), leaving 122 bits of randomness. This means there are over 5.3 undecillion possible v4 UUIDs — the chance of generating a duplicate is astronomically small. This tool uses the Web Crypto API for cryptographically strong randomness.
When should I use UUIDs?
UUIDs are ideal for database primary keys in distributed systems, session identifiers, API request tracking, file naming, and anywhere you need a unique ID without coordinating with a central server. They are widely used in web development, mobile apps, and microservice architectures.
UUID with or without dashes?
The standard UUID format includes dashes (e.g., 550e8400-e29b-41d4-a716-446655440000), but some systems prefer the compact form without dashes (e.g., 550e8400e29b41d4a716446655440000). Both represent the same 128-bit value. Use the "No dashes" option above to generate the compact form.
Is this generator secure?
Yes. This tool uses crypto.getRandomValues(), the browser's cryptographically secure random number generator. UUIDs are generated entirely in your browser — no data is sent to any server. The output is suitable for use as database keys, tokens, and other identifiers.