About UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in software systems without requiring a central authority. This tool generates both UUID v4 — which uses cryptographically random bytes via the Web Crypto API — and UUID v1, which encodes the current timestamp into the identifier structure.

Developers rely on UUIDs as primary keys, correlation IDs, and idempotency tokens across distributed systems. All generation and validation happens entirely in your browser — no network request is ever made, so your identifiers stay private.

Common Use Cases

Generating primary keys for database rows where auto-increment integers would leak record counts
Creating idempotency keys for payment APIs and webhook payloads to prevent duplicate processing
Assigning correlation IDs to distributed log traces so you can follow a request across multiple services
Validating whether a string received from an external API or user input is a well-formed UUID

How to Use

Select v4 (random) or v1 (time-based) using the toggle at the top
Set how many UUIDs you need in the Count field (up to 100 at once)
Click Generate — click any UUID in the list to copy it individually, or use Copy All
To validate an existing UUID, paste it into the UUID Validator panel at the bottom

Frequently Asked Questions

What is the difference between UUID v4 and UUID v1?

UUID v4 is entirely random (122 random bits) and is the most commonly used version for primary keys because there is no deducible structure. UUID v1 embeds a timestamp and a node identifier, which makes the values monotonically increasing but also reveals when the ID was created — a privacy consideration in some contexts.

What does the "No dashes" option do?

The standard UUID format includes four hyphens separating the five groups (e.g. 550e8400-e29b-41d4-a716-446655440000). Some systems — such as certain database column types or URL-safe contexts — require the compact 32-character hexadecimal string without dashes. The No Dashes toggle outputs that format while preserving all 128 bits of the identifier.

How random are the UUIDs generated here?

All v4 UUIDs are generated using crypto.getRandomValues(), which draws from the operating system's cryptographically secure pseudo-random number generator (CSPRNG). This is the same entropy source used for TLS key generation and is suitable for security-sensitive identifiers.