Developer UUID tools
GUID vs UUID
GUID and UUID usually refer to the same 128-bit identifier format. The practical difference is mostly terminology and ecosystem.
GUID vs UUID in simple terms
UUID means universally unique identifier. GUID means globally unique identifier. In everyday development, both names usually describe the same 128-bit value.
GUID is common in Microsoft, Windows, SQL Server, and .NET documentation. UUID is common in standards, Linux, JavaScript, Python, Go, Java, and database documentation.
UUID and GUID examples
UUID example: 123e4567-e89b-42d3-a456-426614174000. GUID example: {123e4567-e89b-42d3-a456-426614174000}. The braces are a display convention, not a different identifier size.
Format and length
Both UUIDs and GUIDs are normally shown as 36 characters with hyphens in an 8-4-4-4-12 pattern. Without hyphens, the value has 32 hexadecimal characters.
Some systems store the value as 16 bytes instead of text, especially databases with native UUID or uniqueidentifier types.
Which should I use?
Use GUID when writing for C#, .NET, Windows, or SQL Server teams. Use UUID when writing cross-platform documentation, API contracts, database schemas, or standards-oriented code.
When naming a public API field, uuid is often clearer for cross-platform users. When naming a .NET property or SQL Server column, guid may match local conventions better.
FAQ
Is a GUID the same as a UUID?+
In most practical developer contexts, yes. GUID is the Microsoft-oriented term, while UUID is the standards-oriented term.
Are GUIDs and UUIDs the same length?+
Yes. Both are commonly represented as 36-character hyphenated strings or 32 hexadecimal characters without hyphens.
Should my API field be called guid or uuid?+
Use uuid for cross-platform APIs unless your product is specifically .NET or Microsoft-focused.