How many UUIDs can I generate at once?

Up to 100 per click. For larger volumes, click Generate again to produce another batch and combine the results.

Are all UUIDs in the batch unique?

Yes. Each UUID is generated independently with crypto.randomUUID(), and the probability of duplicates within a batch of 100 is effectively zero.

Can I download the batch?

Yes. Click the Download button to save all generated UUIDs as a plain text file, one UUID per line, suitable for direct import into a database or test file.

Is the data sent to a server?

All generation runs in your browser using crypto.randomUUID(). Our servers are not involved at any point.

Bulk UUID Generator

Generate up to 100 random UUID v4 values at once for seeding databases, creating test fixtures, or pre-allocating IDs. Each UUID appears on its own line for easy copying or downloading. All generation runs in your browser.

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Runs entirely in your browser

How it works

UUID v4 generation uses the browser's crypto.randomUUID() API, a cryptographically secure random number generator built into every modern browser. No JavaScript library is needed.

Processing runs in your browser

UUIDs are generated entirely in your browser. All processing happens locally in your browser tab. Our servers are not involved at any point. You can inspect this yourselfin your browser's DevTools Network tab.

Technical specification

UUID version 4 (random) is defined in RFC 4122 (IETF, 2005). A UUID v4 contains 122 random bits; the remaining 6 bits encode the version (4) and variant (10xx in bits 64–65). This tool uses the browser's crypto.randomUUID() method (W3C Web Cryptography API), which provides cryptographically strong randomness from the operating system's CSPRNG, equivalent to /dev/urandom on Linux or BCryptGenRandom on Windows.

Standard: RFC 4122: A Universally Unique IDentifier (UUID) URN Namespace
Random bits: 122 bits (of 128 total; 6 bits encode version/variant)
Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
Collision probability: ~50% at 2.7 × 10¹⁸ UUIDs generated

Related operations

For hashing identifiers into fixed-width values, try the hash generator. To produce strong random secrets, use the password generator. For encoding identifiers for transport, see Base64.

Frequently asked questions

How many UUIDs can I generate at once?: Up to 100 per click. For larger volumes, click Generate again to produce another batch and combine the results.
Are all UUIDs in the batch unique?: Yes. Each UUID is generated independently with crypto.randomUUID(), and the probability of duplicates within a batch of 100 is effectively zero.
Can I download the batch?: Yes. Click the Download button to save all generated UUIDs as a plain text file, one UUID per line, suitable for direct import into a database or test file.
Is the data sent to a server?: All generation runs in your browser using crypto.randomUUID(). Our servers are not involved at any point.