🆔 UUID Generator
Generate cryptographically secure random version 4 UUIDs — one or up to 1,000 at once, ready to copy or download.
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier, also called GUID) is a 128-bit identifier written as 32 hexadecimal digits in the pattern 8-4-4-4-12, e.g. 550e8400-e29b-41d4-a716-446655440000. UUIDs are used as database primary keys, request IDs, file names and API resource identifiers because they can be generated anywhere without coordination and still be unique.
What version of UUID does this tool generate?
Version 4 (random) UUIDs, generated with the browser's cryptographically secure random number generator (crypto.randomUUID / crypto.getRandomValues). In a v4 UUID, 122 of the 128 bits are random; the third group always starts with "4" (the version) and the fourth group starts with 8, 9, a or b (the variant).
Can two generated UUIDs collide?
With 2¹²² possible values, the probability is negligible — you would need to generate about 2.7 quintillion UUIDs to reach even a 50% chance of a single collision. For practical purposes, v4 UUIDs are unique.
What is the difference between UUID and GUID?
Nothing in practice — GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit identifier. GUIDs from .NET/SQL Server and UUIDs from other platforms are interchangeable.
Should UUIDs be uppercase or lowercase?
RFC 4122 specifies lowercase for output but says parsers should accept both. Use the UPPERCASE option if your system (e.g. some Microsoft tooling) expects capital letters; the "remove hyphens" option gives the compact 32-character form some databases store.
Are the generated UUIDs sent to a server or logged?
No. UUIDs are generated locally in your browser using the Web Crypto API and never transmitted anywhere — safe to use directly in production systems.