UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit number formatted as 32 hexadecimal digits in five hyphen-separated groups (e.g., 550e8400-e29b-41d4-a716-446655440000). Version 4 UUIDs are generated from random numbers and have a collision probability so low they are considered practically unique across all systems worldwide.

How to Use the UUID Generator

1. Drag the Quantity slider to choose how many UUIDs you need — from 1 to 50.
2. Click Refresh to generate a new batch of random v4 UUIDs.
3. Click the Copy icon next to any individual UUID to copy it to your clipboard.
4. If you need all UUIDs at once, click Copy All to get a newline-separated list.
5. Paste the UUIDs directly into your database, code, or configuration file.

Common Use Cases

• Database primary keys: Use UUIDs instead of auto-increment integers to avoid exposing row counts and to merge records across distributed databases safely.
• API resource identifiers: Assign UUIDs to users, orders, or sessions so IDs are globally unique without coordination between services.
• File and asset naming: Rename uploaded files to UUIDs to prevent collisions and avoid exposing original filenames.
• Idempotency keys: Use a UUID as an idempotency key when making payment or mutation API requests to prevent duplicate processing.
• Testing and fixtures: Generate deterministic-looking but unique IDs for test data and database seed scripts.
• Correlation IDs: Attach a UUID to each request in a microservices architecture to trace it through logs across multiple services.

Why Use an Online UUID Generator?

Most programming languages can generate UUIDs with a library call, but an online generator is faster when you just need a few IDs for a config file, a SQL INSERT statement, or a quick test. This tool uses the browser's native crypto.randomUUID() API — the same cryptographically secure random source used by production software — so the UUIDs are genuine and safe to use anywhere.

Frequently Asked Questions

What is the difference between UUID v4 and v1?

UUID v1 is generated from the current timestamp and the machine's MAC address, making it sortable by time but potentially traceable to a specific machine. UUID v4 is entirely random, offering no time ordering but maximum privacy and unpredictability. v4 is the most widely recommended version for general-purpose use.

Can two UUID v4s ever be the same?

Theoretically yes, but the probability is astronomically small. With 2¹²² possible v4 values (roughly 5.3 × 10³⁶), you would need to generate billions of UUIDs per second for billions of years before a collision became likely. For all practical purposes, treat them as unique.

Is a UUID the same as a GUID?

Yes. GUID (Globally Unique Identifier) is Microsoft's terminology for the same concept defined in RFC 4122. The format and structure are identical — only the name differs depending on the platform or language you are working in.

Related Tools

Explore more free developer tools: Password Generator — create strong random passwords. Hash Generator — hash strings with MD5, SHA-256, and SHA-512. Base64 Converter — encode or decode Base64 strings.