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UUID/GUID Generator
UUID / GUID Generator
Generate RFC4122 Version 4 compliant Universally Unique Identifiers
UUID v4 Batch
UUID v4 uses 122 bits of entropy, making the probability of collision virtually zero.
About the UUID/GUID Generator
Generate random version 4 UUIDs (also called GUIDs) for database keys, tokens, file names and test data.
How to use the UUID/GUID Generator
- Enter the Quantity to Generate.
- Optionally choose Uppercase or wrap each value in Braces { }.
- Press Generate UUIDs and use Copy All or Save.
Formula and method
A UUID is a 128-bit identifier written as 32 hexadecimal digits in five groups: 8-4-4-4-12. Version 4 UUIDs are random apart from a few fixed bits, leaving 122 random bits, so the chance of two matching is negligible.
When to use the UUID/GUID Generator
- Creating unique IDs for database records, files and API objects.
- Generating test data for development.
- Naming resources so they never collide across systems.
Common mistakes to avoid
- Using UUIDs as secret tokens. They are identifiers and not always unpredictable.
- Storing them as long text in a database when a binary column is more efficient.
Tips
- UUIDs are unique identifiers, not secrets. Do not use them as passwords or access tokens.
- Random UUIDs are not sorted, which can affect database index performance for very large tables.
Frequently Asked Questions
They are the same thing. GUID is the term commonly used by Microsoft.
It is theoretically possible but extremely unlikely. A random version 4 UUID has 122 random bits.
Five groups of hexadecimal digits separated by hyphens, such as 123e4567-e89b-12d3-a456-426614174000.