UUID Generator – Create UUID v4 Online

Generate one or multiple random UUID v4 identifiers. Choose uppercase or remove hyphens, then copy the list for application records and test data.

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About UUIDs:

UUID v4: Randomly generated, most commonly used
Time-based v1-like: a custom timestamp and random-data identifier. It does not use your device MAC address and is not standard UUID v1.
UUIDs are 128-bit identifiers that are globally unique
Format: xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx (M = version, N = variant)

Generate one or multiple random UUID v4 identifiers. Choose uppercase or remove hyphens, then copy the list for application records and test data.

Generate UUID v4 identifiers

A UUID is a 128-bit identifier commonly written in five groups separated by hyphens. The v4 option creates random identifiers for records, test data, and application fixtures. The time-based option is labeled v1-like because it is a custom format, not a standards-compliant UUID v1.

When to use a UUID generator

Build development fixtures

Create sample identifiers for database rows, mock API responses, and local tests without keeping a manual counter.

Create record IDs

Use v4 when an application accepts random identifiers and performs its own uniqueness checks.

How to create UUIDs

Choose v4 or v1-like and select one of the available batch sizes: 1, 5, 10, 25, 50, or 100. Generate the identifiers, then copy one value or the full list. Optional controls use uppercase or remove hyphens; you can also remove individual values or clear the list.

UUID examples for development

Seed a test database

Generate IDs for mock users or products and copy the list into a fixture or seed file.

Check an integration

Paste a v4 value into a form or API test to verify that an identifier field accepts the expected format.

Tips for using generated UUIDs

Use v4 for standard random UUIDs

Choose v4 when your application expects a standard random UUID; v1-like is not a compliant v1 value.

Keep the expected format

Leave hyphens and lowercase enabled unless the receiving system accepts compact or uppercase values.

Enforce uniqueness in your app

A v4 collision is extremely unlikely but not impossible. Keep a uniqueness constraint where identifiers are stored.

Browser support

The v4 option uses crypto.randomUUID, available in current browsers in secure contexts such as HTTPS. Identifiers are generated in the browser; clipboard permissions can affect copying.

What to check before using the result

The timestamp option is labeled v1-like and is not a standards-compliant UUID v1 generator. Use v4 when your application expects standard random UUIDs; check whether it requires the normal hyphenated format.

Frequently Asked Questions

Are UUID v4 values guaranteed to be unique?

No generator can guarantee global uniqueness without coordination. A v4 collision is extremely unlikely, but applications should still enforce a unique constraint.

What does v1-like mean?

It is a custom timestamp-based option, not a standards-compliant UUID v1. It does not use a device MAC address and should not be treated as a canonical v1 value.

Can I remove hyphens or use uppercase?

Yes. Toggle the formatting options before generating and confirm that your database or API accepts the selected format.

How can I make and copy a batch of UUIDs?

Choose one of the available batch sizes: 1, 5, 10, 25, 50, or 100, generate the values, then use the copy controls on the displayed list or entries.

How long is a UUID with or without hyphens?

The usual UUID text form has 36 characters including four hyphens; removing them leaves 32 hexadecimal characters.

Can I use a UUID as a password or authentication token?

No. A UUID is an identifier, not a secret or an authentication mechanism. Use a purpose-built, securely generated token for access control.