---
title: "UUID Generator"
description: "Generate UUIDs in your browser: Version 1 (time-based), Version 4 (random), Version 7 (Unix time-ordered), and Nil/Empty UUID. Bulk generation up to 1000 at once. Nothing leaves your device."
url: "https://freshjuice.dev/tools/uuid-generator/"
---
## About UUID versions

-   **Version 1** — Time-based, with a clock sequence and node ID. Useful when you want sortable identifiers tied to creation time. Our implementation uses a random multicast node ID per session for privacy (we don't leak your real MAC address).
-   **Version 4** — Purely random (122 bits of randomness). The classic, general-purpose choice. No time leakage, no node leakage.
-   **Version 7** — Time-ordered using Unix epoch milliseconds plus randomness ([RFC 9562](https://datatracker.ietf.org/doc/html/rfc9562)). Sorts chronologically while remaining unique — plays much nicer with database B-tree indexes than v4 when used as a primary key.
-   **Nil / Empty** — All zeros: `00000000-0000-0000-0000-000000000000`. Often used as a sentinel value or placeholder.

All UUIDs are generated locally in your browser using the secure `crypto.getRandomValues` API. Nothing is sent to our servers.

## v4 or v7 — which should I use?

For most cases, **v7** is now the better default. It keeps the randomness benefits of v4 but adds a time prefix that makes database indexes happier (sequential inserts, fewer page splits) and makes debugging easier (you can sort logs by ID).

Use **v4** when you specifically don't want any time information leaked, or when you need maximum compatibility with older tooling that doesn't recognize v7 yet.

## Frequently Asked Questions

### Are these UUIDs unique?

The collision probability for v4 is astronomically low — 122 bits of randomness means you'd need to generate billions per second for thousands of years to expect a single collision. v7 inherits this property for the random portion (74 bits) per millisecond.

### Why not always use v1?

v1 includes the machine's MAC address by default, which is a privacy leak. Our implementation replaces it with a random multicast node, but most modern systems prefer v7 for time-ordered IDs.

### How many UUIDs can I generate at once?

Up to 1000 per click. Pasting 1000 random UUIDs into a database, seeding a test fixture, or generating example data — all reasonable. For higher counts, run the tool multiple times.

### Where do I learn more?

[RFC 9562](https://datatracker.ietf.org/doc/html/rfc9562) is the current spec covering v1, v4, v6, v7, and v8. The historical spec was [RFC 4122](https://datatracker.ietf.org/doc/html/rfc4122).

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**Disclaimer:** The UUIDs generated by this tool are provided *as-is*, without warranty of any kind — not even the warranty that they are actually unique. You are responsible for using them and assume any risk inherent to using them. Do not use any UUIDs found on cached versions of this page.