Online UUID Generator
Generate UUID v4 (GUID) instantly — single or bulk. Free online UUID generator, no signup required. All generation happens in your browser.
💡 About UUID v4: A UUID (Universally Unique Identifier) version 4 is a randomly generated 128-bit identifier. The probability of generating a duplicate is extremely low, making them perfect for database keys, session IDs, and unique identifiers.
UUID Format & Structure
A UUID v4 is a 128-bit number displayed as 32 hexadecimal digits in 5 groups separated by hyphens: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
| Section | Characters | Bits | Notes |
|---|---|---|---|
| time_low | 8 | 32 | Random in v4 |
| time_mid | 4 | 16 | Random in v4 |
| time_hi_version | 4 | 16 | First digit always 4 (version) |
| clock_seq | 4 | 16 | First digit is 8, 9, a, or b (variant) |
| node | 12 | 48 | Random in v4 |
Generate UUID in Code
crypto.randomUUID()
import { v4 as uuidv4 } from 'uuid';
const id = uuidv4();import uuid id = str(uuid.uuid4())
import java.util.UUID; String id = UUID.randomUUID().toString();
var id = Guid.NewGuid().ToString();
import "github.com/google/uuid" id := uuid.New().String()
What is a UUID Used For?
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify information across distributed systems without a central coordinating authority. Because the probability of collision is astronomically low (1 in 2¹²²), UUIDs are safe to generate independently on any machine and trust they'll be globally unique.
Database Primary Keys
Instead of auto-increment integers, UUID primary keys work across distributed databases, microservices, and offline-first apps without collision.
Session & Auth Tokens
Web sessions, API tokens, and password reset links use UUIDs to create unguessable, unique identifiers for each user session.
File & Asset Names
Uploaded files are often renamed to UUIDs to prevent filename collisions and avoid exposing original filenames in cloud storage.
Message Queue IDs
Every message in systems like RabbitMQ, Kafka, or AWS SQS gets a UUID so messages can be tracked, deduplicated, and acknowledged.
Transaction Tracking
Payment processors, order systems, and audit logs use UUIDs as transaction IDs to trace operations across multiple services.
Test Data & Fixtures
Generate bulk UUIDs to seed databases with realistic test data that won't conflict across environments.
Frequently Asked Questions
Common questions about UUID Generator