UUID Generator

Generate secure UUID v4 values with browser-native cryptographic randomness.

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RFC 4122 variant • UUID version 4

    Tool documentation

    Generate secure UUID v4 identifiers in your browser

    Create RFC-compatible random identifiers for databases, fixtures, tests, and distributed systems without calling an identifier API.

    100% Client-Side

    Conversion runs locally in your browser.

    No Payload Logging

    Your tool input is never uploaded or logged.

    Private by Design

    Input stays on your device and is not persisted.

    How to use

    1. 1

      Choose a batch size

      Select how many UUID v4 values you need. Small and larger development batches can be generated without a server request.

    2. 2

      Generate secure identifiers

      Create a fresh batch with browser-native cryptographic randomness and RFC-compatible UUID version and variant bits.

    3. 3

      Copy or download

      Copy the full batch to your clipboard or download newline-separated UUIDs for fixtures, migrations, and local development.

    Technical details

    Cryptographic randomness

    Modern browsers use crypto.randomUUID when available, with a crypto.getRandomValues fallback. DevCrate does not rely on Math.random for UUID generation.

    Version and variant bits

    UUID v4 reserves specific bits for the version and RFC variant. The remaining random bits create an enormous identifier space suitable for ordinary application identifiers.

    Uniqueness is probabilistic

    Random UUID collisions are extraordinarily unlikely, but not mathematically impossible. Systems that require absolute uniqueness should still enforce a unique database constraint.

    Privacy & security verification

    UUID generation uses browser-native cryptographic randomness. Generated identifiers stay in this tab unless you copy or download them. No UUID batch is uploaded or persisted by DevCrate.