UUID generator
Generate one or more random v4 UUIDs.
The UUID generator produces one or more version-4 (random) UUIDs, with options for uppercase formatting and whether to include hyphens — copy a single value or all of them at once for use in code, databases, or configuration.
How to use
- Set how many UUIDs you need, and your formatting preferences.
- Click "Generate", then copy any value or all of them at once.
Common use scenarios
- Generating unique identifiers for database records or test data.
- Creating placeholder IDs while prototyping an application.
- Producing a batch of UUIDs for seeding a data set.
- Getting a quick unique string for a one-off configuration or file name.
✓Content & verification reviewed: 2026-08-25
How we verify UUID generator
How to confirm the generated UUIDs suit your intended use.
Uses the browser's crypto API when available, with a fallback
The generator prefers the browser's built-in cryptographically secure random number source, falling back to Math.random only if that's unavailable — this makes it suitable for general-purpose unique identifiers, but not a substitute for a security-critical ID scheme where unpredictability must be guaranteed.
Formatting options don't affect uniqueness
Uppercase and hyphen settings only change how the UUID is displayed — the underlying random value and its uniqueness properties are the same either way, so pick formatting based on what your target system expects, not based on any effect on randomness.
Each UUID generated is independent of the others in a batch
When generating multiple UUIDs at once, each one is produced independently — there's no relationship or ordering between them beyond being generated in the same batch, so you can safely use any subset without affecting the others.
Before you rely on the result
- You've set the count to how many UUIDs you actually need.
- Uppercase and hyphen formatting match what your target system (database, code, config file) expects.
- You understand this uses a fallback to Math.random in environments without the crypto API, which is fine for general use but not for security-critical secrets.
- You've copied the values you need before navigating away, since they aren't saved anywhere.
Who this is for
- Developers generating unique identifiers for database records or test data.
- Anyone creating placeholder IDs while prototyping an application.
- People producing a batch of UUIDs for seeding a data set.
- Anyone needing a quick unique string for a one-off configuration or file name.
Real-world examples
Seeding test data
A developer populating a test database with sample records generates a batch of UUIDs to use as unique primary keys for each row.
Prototyping an application
Someone building an early prototype needs placeholder unique IDs before a real ID-generation system is wired up, and generates a handful of UUIDs to use temporarily.
One-off unique file or config naming
A person needing a guaranteed-unique string for a temporary file name or config key generates a single UUID and copies it directly.
Limitations
- Generated with the browser's crypto API when available, falling back to Math.random — fine for general use, not a substitute for a security-critical ID scheme.
Frequently asked questions
Are these UUIDs cryptographically secure?
They use the browser's cryptographically secure random source when available, falling back to Math.random otherwise — this is fine for general-purpose unique IDs, but not a substitute for a security-critical identifier or secret.
Does uppercase or removing hyphens change how unique the UUID is?
No — formatting options only affect the displayed text; the underlying randomness and uniqueness of the UUID are unchanged either way.
Can two generated UUIDs collide?
It's astronomically unlikely with version-4 UUIDs — the random value space is large enough that collisions aren't a practical concern for typical use.
Are the UUIDs I generate saved anywhere?
No — copy the values you need before leaving the page, since nothing is stored after you navigate away.
🔒 Runs in your browser — nothing is uploaded. Results are for reference only; see the disclaimer. Last updated: 2026-08-25
Subscribe for updates
New tools and tips, straight to your inbox. No spam, unsubscribe anytime.