Need a unique ID for a database row, API request, or session token? Use our free UUID Generator to create random v4 UUIDs instantly — one at a time or in bulk.
What Is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier designed to be unique across systems without central coordination. Instead of relying on a shared database counter, each UUID is generated independently — making it ideal for distributed applications, API request IDs, session tokens, and primary keys where collisions must be practically impossible.
Why UUIDs Are Practically Collision-Free
The random UUID v4 address space contains roughly 5.3 × 10³⁶ possible values. At that scale, accidental duplicates are statistically negligible — even if billions of UUIDs are generated across millions of systems, the probability of a collision remains astronomically small. This is why UUIDs are trusted as database primary keys and distributed system identifiers without a central ID server.
UUID v4 and Other Versions
This tool generates UUID version 4 — the most common format, based on random data. Other versions exist for different use cases: v1 incorporates timestamp and MAC address data, while v5 derives identifiers from names using a hash. For most modern development work — APIs, databases, and session management — v4 is the standard choice.
Frequently Asked Questions
What is a UUID used for?
UUIDs are commonly used as unique identifiers for database records, API requests, and distributed systems where IDs need to be generated independently without a central counter or coordination.
Can two UUIDs ever be the same?
Theoretically possible but practically negligible — the random UUID v4 address space is large enough that accidental duplicates are astronomically unlikely even at massive scale.
What's the difference between UUID v4 and other versions?
v4 is randomly generated (what this tool produces), while other versions like v1 incorporate timestamp/MAC address data or are derived from names — different versions suit different use cases.
Do I need hyphens in a UUID?
Hyphens are the standard display format (8-4-4-4-12 character groups), but some systems accept or require UUIDs without hyphens — this tool supports both.
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