UUID Generator
Generate cryptographically secure UUID v4 identifiers — one or up to a hundred at a time — using your browser's native random source.
Generate IDs
Nothing leaves your deviceYour UUIDs
How to use this generator
- Choose a count — from a single ID up to 100 for seeding test data or fixtures.
- Pick the case if your system expects uppercase identifiers.
- Press Generate. Fresh v4 UUIDs appear instantly, one per line, with the version and variant confirmed in the status line.
- Copy all to grab the whole list at once, then generate again for a new batch.
Useful information
A UUID (Universally Unique Identifier) is a 128-bit label defined by RFC 9562. In its familiar v4 form, 122 bits are random and the rest encode the version (4) and variant — producing the pattern xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where y is 8, 9, a or b.
Where the randomness comes from
This tool calls crypto.randomUUID() when available and otherwise assembles the value from crypto.getRandomValues() — the same CSPRNG your browser uses for session tokens. It never falls back to Math.random().
Collisions: a non-issue
With 2^122 possible values, you'd need to generate billions of IDs per second for billions of years before a duplicate became likely. For databases, feature flags and test fixtures, v4 UUIDs are safe to treat as unique.
v4 vs other versions
v1/v2 embed timestamps and MAC addresses (useful for sorting, but they leak creation time and hardware details). v5/v6/v7 use hashing or time-ordering schemes. For anonymous, unordered identifiers, v4 remains the standard default — and it's what this tool produces.
Frequently asked questions
What is a UUID?
A Universally Unique Identifier is a 128-bit value written as 36 characters in the form 8-4-4-4-12 (for example 550e8400-e29b-41d4-a716-446655440000). It's designed to be unique across systems without coordination.
How are these UUIDs generated?
Version 4 UUIDs are mostly random: 122 of 128 bits come from your browser's cryptographically secure random source (crypto.randomUUID or crypto.getRandomValues), with the version and variant bits set correctly.
How likely is a duplicate?
Effectively zero for normal use. With 2^122 random bits, generating a billion IDs per second for a billion years still makes a collision extraordinarily unlikely.
What is the difference between UUID v4 and v1?
v1 embeds a timestamp and MAC address, so it reveals when it was made and can leak hardware details. v4 is fully random, which is why it's the usual choice for identifiers.
Are the generated UUIDs stored or logged?
No. They're created and displayed in your browser only — Jivora never sees, stores or logs them.