Free Online Random UUID Generator

What is a UUID?

UUIDs stands for Universally Unique IDs (aka GUIDs) are a type of 128-bit number that can be used to generate unique values across many computers and across time. Because of their uniqueness, they are useful for primary keys in situations where auto-incremented values might be duplicates. Since UUIDs are guaranteed to be unique, UUIDs are useful for generating random test data. Need a random string? A UUID is fine. What about an email? UUID@UUID.com is a great example of a generated ID, or use any other format that makes sense for your program.

What is UUID used for?

When you need a number to identify something, it’s best to use UUIDs. UUIDs are system-generated globally unique identifiers typically used for computer systems, networks, and other types of information that need to be unique and do not repeat. They’re also randomly generated, so no one has control over them, and there is no way to predict the next one, which makes them handy to use anywhere.

What is a Random UUID generator?

A random UUID generator is an online software tool that generates universally unique identifiers using a variant of the “random” algorithm specified in RFC 4122. This algorithm generates a random 128-bit number, which is then formatted as a string of hexadecimal characters in a specific format (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx). The random algorithm is intended to generate UUIDs that are unique across all devices and at all times by using a high-quality pseudorandom number generator (PRNG) to generate the 128-bit value and ensure that there is a meager chance of collision between UUIDs that are generated.

How does UUID work?

The Universally Unique Identifier uses a 128-bit sequence of hexadecimal characters to ensure uniqueness. The ID is composed of Hexadecimal numbers. Meaning the numbers 0-9 and the letters A-F. The hexadecimal digits are paragraphed in 32 groups of four hyphens. It's presented in the format XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX, with each of the four hyphens representing 8 bits (or one hexadecimal character). The last segment of a four-segment code, the N position, indicates such things as format and encoding in a single to three bits.

How do I create my own UUID?

UUID (aka GUID) is a 128-bit number formatted into blocks of hexadecimal digits separated by a hyphen. A typical UUID is 805a4340-d5e0-4587-8f04-0ae88219699f. It doesn't matter whether the letters A-F are upper or lower case. RFC 4122 defines version-4 UUIDs as 128 bits generated in such a way that six bits at certain positions have particular values. For example, 805a4340-d5e0-4587-8f04-0ae88219699f. The digit at position 13th is always "4" and the digit at position 16th is always one of "8", "9", "A/a" or "B/b". The procedure to generate your own version-4 UUID is as follows:

1. Generate 16 random bytes (=128 bits)

2. Adjust certain bits according to RFC 4122.

3. Encode the adjusted bytes as 32 hexadecimal digits.

4. Add four hyphen "-" characters to obtain blocks of 8, 4, 4, 4 and 12 hex digits.

5. Output the resulting 36-character string "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX".