Free UUID Generator Online

What Is a UUID?

A UUID (Universally Unique Identifier) — also called GUID (Globally Unique Identifier) on Windows systems — is a 128-bit identifier designed to be unique across all computers and networks, without requiring a central authority to coordinate.

A UUID looks like this: 550e8400-e29b-41d4-a716-446655440000

It consists of 32 hex characters divided into 5 groups: 8-4-4-4-12, for a total of 36 characters including hyphens.

UUID v4 vs UUID v1

Common Use Cases

• Database primary keys — UUIDs are often used instead of auto-incrementing integers, enabling distributed systems to generate IDs without coordination.
• API request tracing — Assign a UUID to each API request for distributed tracing and log correlation.
• Session tokens — Generate unique session IDs that cannot be guessed or enumerated.
• File naming — Rename uploaded files with UUIDs to prevent collisions and directory traversal attacks.
• Idempotency keys — APIs like Stripe use UUIDs as idempotency keys to prevent duplicate charges.

Generating UUIDs in Code

// Browser & Node 19+
crypto.randomUUID()

// Node.js (older)
const { v4: uuidv4 } = require('uuid');
uuidv4();

import uuid
uuid.uuid4()
# '550e8400-e29b-41d4-a716-446655440000'

import "github.com/google/uuid"
uuid.New().String()

-- Enable extension once:
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";

SELECT uuid_generate_v4();