UUID Generator Online — v4, v7 & Nil

Generate random UUID v4, time-ordered UUID v7, or the nil UUID. Control hyphens, uppercase, format variants (braces, URN), and how many IDs you need (1–50) for fixtures and seed data.

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UUID generator — developer notes
Create RFC-style UUIDs for tests, seeds, and client IDs. v4 is random; v7 is time-sortable; nil is the all-zero sentinel.

UUID or GUID? v4 vs v7

UUID and GUID both name a 128-bit identifier—GUID is Microsoft’s label for the same idea described in RFC UUID documents. This page is a UUID generator for everyday choices: v4 when you need unpredictable random IDs, and v7 when you want time-ordered values that sort roughly by creation time (useful for database indexes and log correlation). The nil UUID remains available as an all-zero sentinel for tests. Pick hyphens, case, plain vs braces vs URN, and how many IDs to emit (1–50; nil always returns one). Lists refresh when options change; copy or download locally with Web Crypto. For Crockford Base32 IDs, try the ULID generator; for shorter tokens, see the Nanoid generator.

How generation works

Choose a version, optional formatting (hyphens, uppercase, braces, URN), and a count from 1 to 50. The list fills immediately and refreshes when you change an option — copy one line or everything, or download as .txt.

Options

Version (v4 / v7 / nil)
v4 is cryptographically random. v7 embeds a Unix timestamp for sortable IDs (shown per row). Nil returns 00000000-0000-0000-0000-000000000000 (or the hyphenless form).
Hyphens
Keep standard 8-4-4-4-12 form, or strip hyphens for APIs and databases that expect 32 hex characters.
Uppercase
Emit A–F instead of a–f when consumers are case-sensitive or expect uppercase hex.
Count (1–50)
Generate multiple IDs for fixtures without flooding the page — capped at 50.
Format wrap (plain / braces / URN)
Plain leaves the UUID as formatted above. Braces wraps it in {}. URN prefixes urn:uuid: and forces canonical lowercase with hyphens — both hyphens and uppercase toggles are disabled while URN is selected.

Examples

v4 with hyphens

Settings

version=v4, hyphens=on

Sample output

550e8400-e29b-41d4-a716-446655440000

v7 uppercase, no hyphens

Settings

version=v7, hyphens=off, uppercase=on

Sample output

018E2F3A4B5C6D7E8F90123456789ABC

Related utilities

For time-sortable IDs, the ULID generator; for compact IDs, the Nanoid generator. Convert timestamps with the Unix timestamp tool.

UUID generator FAQ

ID generation questions

When should I use UUID v7?

Use v7 when you want IDs that roughly sort by creation time (indexes and debugging). Prefer v4 when you only need random uniqueness.

Is generation private?

Yes. UUIDs are created in your browser with Web Crypto when available.

Why is count capped at 50?

Bulk fixtures are useful; huge dumps are better handled in scripts. Fifty keeps the UI focused while the slider stays practical.

What is the nil UUID for?

It is a reserved all-zero value used as a sentinel or “empty” UUID in some protocols and tests.

Is a GUID the same as a UUID?

In practice, yes for developers: both refer to 128-bit unique identifiers. GUID is the name common in .NET and Windows docs; UUID is the RFC term this tool follows when generating v4, v7, or nil values.

How do I generate several UUIDs at once?

Use the Count slider (1–50). Each refresh produces that many lines—copy one row, copy all, or download as .txt. The nil version ignores bulk and always returns a single all-zero ID.

Developer utilities

Timestamps, UUID, ULID, Nanoid, cron, passwords, regex, slugify, number bases, case, text diff, and chmod — all client-side.

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