UUID Generator

About the UUID Generator

A UUID (Universally Unique Identifier), also known as a GUID in the Microsoft world, is a 128-bit identifier that is practically guaranteed to be unique without needing a central authority. Version 4 UUIDs are generated from random numbers and look like 3f2b8c1e-9d4a-4b7e-8f21-6c5d9e0a1b2c.

Developers use UUIDs as database primary keys, API request IDs, file names, session tokens and test data. This UUID Generator uses your browser's cryptographically secure random number generator and can create up to 5,000 UUIDs at once. Format them in uppercase, without hyphens or wrapped in braces, then copy or download the list.

How to read a UUID and where to use it

A version 4 UUID such as 3f2b8c1e-9d4a-4b7e-8f21-6c5d9e0a1b2c has 32 hexadecimal characters in five groups (8-4-4-4-12). The first character of the third group is always 4, which marks the version. The first character of the fourth group is 8, 9, a or b. Everything else is random.

Format options and when to pick them

• Standard lowercase (3f2b8c1e-…): the safe default for databases, APIs and JSON.
• Uppercase: some Windows tools and older systems display GUIDs this way.
• No hyphens (32 characters): handy for file names and short URLs.
• Braces ({3F2B8C1E-…}): the classic Microsoft registry and .NET style.

Practical tips

• Generate a batch at once when you need test data, for example 500 IDs for rows in a spreadsheet, then download the list.
• Do not use a UUID as a password or secret token in place of a proper one. It is random and unique, but it is meant to identify things, not to protect them.
• In databases with heavy inserts, random UUIDs as primary keys can slow down indexes. Many teams keep an auto-increment ID internally and use the UUID as the public ID.

How to use the UUID Generator

1. Enter how many UUIDs you need.
2. Choose uppercase, no hyphens or braces formatting.
3. Click Generate UUIDs.
4. Copy all or download them as a text file.

Frequently asked questions