UUID / GUID Generator: Version 4 UUIDs, Uniqueness and Formats

What is it?

The UUID / GUID Generator makes random version 4 UUIDs, such as 3f2b8c1e-9d4a-4f6b-a2c7-1e5d9b0a7c34, for database keys, test data and file names.

Who is it for?

Developers needing unique IDs for databases, APIs and files, testers creating sample data, and IT staff generating identifiers for systems.

How to use it

1. Set How many (1 to 10,000) and tap Generate.
2. Copy all or Download them as a text file, one per line.

Are they really unique?

Each v4 UUID has 122 random bits from your browser’s secure random generator. The chance of two ever matching is so small it can be ignored, even across billions of IDs.

Formats

• GUID is Microsoft’s name for the same thing; some tools show it in capitals or with { } braces. Both are the same value.
• Databases: PostgreSQL has a uuid type; in MySQL store it as CHAR(36) or convert to BINARY(16) to save space.
• The “4” at the start of the third group shows the version.

Good to know

UUIDs are random, not secret. Don’t use them as passwords or reset tokens. Random v4 UUIDs also don’t sort by time; if you need time-ordered IDs, look at UUID v7.

Errors and how to fix them

• Database rejects the UUID: the column may expect no dashes or a binary type; convert accordingly.
• Page slow with many: generating 10,000 is fine, but copying huge lists on old phones can lag; use Download.

Open the tool: UUID / GUID Generator

Still stuck?

Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.