UUID Generator
Generate cryptographically random version 4 UUIDs, one or up to a hundred at a time.
Ta treść jest po angielsku.
Rozwiązane przykłady
Generating test row identifiers
Count set to 10 with dashes and lowercase letters
Ten lines, each a random version 4 UUID in the form xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where y is 8, 9, a or b. The values are random, so no fixed list can be shown.
Every line is generated fresh on each click, which is what makes the identifiers unique for practical purposes.
Uppercase IDs without dashes
Count set to 1 with dashes removed and uppercase letters ticked
One line of 32 uppercase hexadecimal characters, such as 3F2B8C1E9A4D4B7F8E2A1C6D9B0F5E47, though the exact value is random.
Removing the dashes gives a compact form that some databases and systems expect, and the characters are still random.
O narzędziu UUID Generator
A UUID, or universally unique identifier, is a 128-bit value written as 32 hexadecimal digits in five groups separated by hyphens. Version 4 UUIDs are generated from random numbers, so each one is produced without reference to a central registry or the machine's address. Collisions are extremely unlikely, which makes them convenient for database keys, request IDs and file names.
This generator produces up to 100 version 4 UUIDs in one go, which is useful when you need a batch of test fixtures or seed data. You can choose uppercase letters or keep the standard lowercase, and include or remove the hyphens to match the format your system expects. Each value follows the version 4 layout, with a fixed version digit and variant bits.
Jak korzystać z narzędzia UUID Generator
- Enter how many UUIDs you need, up to 100.
- Choose uppercase or lowercase letters for the output.
- Decide whether to keep the hyphens or remove them.
- Generate the list and copy the values into your code, fixture or spreadsheet.
Typowe zastosowania
- Creating primary keys for database rows that do not rely on auto-incrementing numbers.
- Generating request IDs to trace calls through a distributed system.
- Seeding test data with realistic, unique identifiers.
- Naming uploaded files so that they do not overwrite each other.
Najczęstsze pytania
Are version 4 UUIDs truly unique?
They are not guaranteed to be unique, but the chance of two random version 4 UUIDs matching is so small that it is ignored in practice. The version 4 format has 122 random bits, giving about 5.3 times 10 to the power of 36 possible values. Systems that need certainty use a database uniqueness constraint as a final check.
What is the difference between UUID version 4 and version 1?
Version 1 UUIDs combine a timestamp with the MAC address of the generating machine, so they can reveal when and where they were created. Version 4 UUIDs use random numbers instead, so they reveal neither. Version 4 is the usual choice when the identifier should not expose that information. Version 1 values are also more predictable, which is another reason many applications prefer version 4.
Can I generate UUIDs without writing code?
Yes. A generator like this produces the identifiers directly, so you can copy them into a spreadsheet, a fixture file or a database seed script. Many programming languages also offer a built-in UUID function, which is useful when identifiers are needed at runtime.
Should UUIDs be uppercase or lowercase?
Either works, because hexadecimal digits are case-insensitive in the standard. Lowercase is the usual form in APIs and many databases. Some legacy systems and older tools default to uppercase. Pick one convention for the whole project, and compare values case-insensitively if they come from different sources.
Is a UUID the same as a GUID?
In practice, yes. GUID is the name used in some ecosystems for the same 128-bit identifier format, and the two terms are usually treated as interchangeable. The main difference is presentation: some systems write GUIDs with braces or in uppercase. The underlying value and the 8-4-4-4-12 layout are the same.