Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit value used to uniquely identify information in computer systems. UUIDs are formatted as 32 hexadecimal digits separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. They are widely used as database primary keys, session tokens, and identifiers in distributed systems.
UUID v4 vs UUID v7
UUID v4 is randomly generated using a cryptographically secure random number generator, making collisions statistically impossible. UUID v7 embeds a Unix timestamp in the first 48 bits, making values time-ordered and sortable. This makes UUID v7 significantly more efficient for database indexing than v4, as sequential inserts avoid index fragmentation. Use v4 for general-purpose identifiers and v7 when database performance is a concern.
How to generate UUIDs
Select the UUID version (v4 or v7) and the number of UUIDs to generate (1, 5, 10, or 25). UUIDs are generated immediately in your browser using the Web Crypto API. Click "Copy" next to any UUID to copy it individually, or use "Copy All" to copy the full list. Click "Regenerate" to produce a fresh batch.
Are these UUIDs cryptographically secure?
Yes. NexKit generates UUID v4 values using the browser's built-in crypto.randomUUID() function, which uses a cryptographically secure pseudo-random number generator (CSPRNG). UUID v7 values use crypto.getRandomValues() for their random bits. All generation happens locally in your browser — no UUIDs are transmitted to any server.