A free online UUID (Universally Unique Identifier) generator that creates v4 UUIDs for use as database keys, API identifiers, and unique references. Generate single or batch UUIDs instantly with no server communication.
Format Options — Lowercase, uppercase, with or without hyphens
Copy Individual or All — Copy single UUIDs or the entire batch
Instant Generation — UUIDs created instantly via browser crypto API
100% Client-Side — Generated using crypto.getRandomValues(), never leaves browser
How to Use
Click Generate to create a single UUID.
For batch generation, enter the number of UUIDs you need (up to 100).
Choose between lowercase and uppercase format.
Copy individual UUIDs or the entire batch with one click.
Use Cases
Database Primary Keys:Generate unique, collision-resistant IDs for database records without sequential numbering.
API Resource IDs:Create unique identifiers for REST API endpoints and resource references.
Session Tokens:Generate random tokens for user sessions, CSRF protection, and authentication.
Distributed Systems:Use UUIDs for unique IDs across distributed databases without coordination.
Tips
Tip: UUID v4 is the most common version — it uses random numbers. If you need time-ordered UUIDs, consider UUID v7 (time-based, sortable).
Tip: Store UUIDs as 36-character strings (with hyphens) or 16-byte binary values for optimal database performance.
Alternatives
Command Line — uuidgen on Linux/Mac
Python — import uuid; str(uuid.uuid4())
Node.js — require("crypto").randomUUID()
FAQ
A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. It is typically displayed as 32 hexadecimal characters separated by hyphens (like 550e8400-e29b-41d4-a716-446655440000).
UUID v4 is a randomly generated UUID. All 122 of its bits are random, giving approximately 5.3 × 10^36 possible unique values. This makes collisions astronomically unlikely — you could generate a billion UUIDs per second and still not expect a duplicate for billions of years.
UUID v4 cannot be predicted because it uses cryptographically secure random number generation (crypto.getRandomValues in browsers). Earlier versions like UUID v1 can be partially predicted since they include timestamps and MAC addresses.
GUID (Globally Unique Identifier) and UUID are essentially the same concept. GUID is Microsoft's implementation of the UUID standard. They use the same format and are interchangeable in most contexts.
Use UUIDs when you need globally unique IDs across distributed systems, when IDs must be generated before saving to a database, or when you want to hide database structure from API consumers. Auto-increment IDs are simpler and more efficient for single-database applications.