UUID Generator
Generate unique UUIDs v1/v4 for databases and APIs
How to use UUID Generator
Generate unique UUIDs v1 and v4 for databases, APIs and software development. Bulk generation supported. Free tool, no signup.
What is a UUID used for?
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information in computer systems. The probability of generating two identical UUIDs is astronomically small — making them practically collision-free.
Common uses:
- Database primary keys: Instead of auto-incrementing integers, UUIDs prevent ID collisions when merging databases or running distributed systems.
- REST APIs: Resource identifiers in URLs like
/users/550e8400-e29b-41d4-a716-446655440000are more secure than sequential IDs. - Session tokens: UUIDs serve as unique session identifiers that are hard to guess or enumerate.
- File naming: Avoid filename conflicts by using UUIDs for uploaded files.
- Event tracking: Analytics systems use UUIDs to track unique events across distributed services.
v1 vs v4: UUID v1 is based on the current timestamp and your MAC address, making it sortable but potentially revealing. UUID v4 is entirely random and the most widely used choice for security-sensitive applications.
Frequently Asked Questions
What is the difference between UUID v1 and v4?
UUID v1 is generated from the current timestamp and the device's MAC address. It is time-sortable but can expose hardware information. UUID v4 is randomly generated, offering better privacy and security — it is the recommended choice for most applications.
Are UUIDs truly unique?
Practically yes. The chance of generating a duplicate UUID v4 is 1 in 2^122 — about 5.3×10^36. You would need to generate billions of UUIDs per second for millions of years before a collision becomes likely.
Can I use a UUID as a password?
No. UUIDs are not designed for security — they are identifiers, not secrets. For passwords, use a dedicated password generator that creates random strings with a mix of character types.
Is UUID the same as GUID?
Yes. GUID (Globally Unique Identifier) is Microsoft's term for the same concept. The format and generation method are identical.
Can UUIDs be sorted chronologically?
UUID v1 can — it encodes a timestamp. UUID v4 cannot, as it is fully random. If you need sortable unique IDs, consider UUID v7 or ULID instead.
UUID v4 vs other unique ID formats
UUID v4 is the universal standard — supported natively in every major database, programming language and framework. ULID (Universally Unique Lexicographically Sortable Identifier) adds chronological sorting. Snowflake IDs (used by Twitter/X) are shorter and sortable but require a server component. Auto-increment integers are simpler but expose record counts and break in distributed systems. For most projects, UUID v4 is the safest and most portable choice.