UUID Version
UUID v3 Generator
Create version-3 UUIDs from a name and a namespace. Because the mapping is deterministic, v3 is ideal for stable identifiers derived from existing keys such as URLs, DNS names or email addresses.
Name-based v3 (RFC 4122)MD5 hashingDeterministic output
Generated locally with the Web Crypto API — nothing leaves your browser.
What Is UUID v3 Generator?
- A UUID v3 is computed by hashing a namespace UUID together with a name using MD5, then setting the version and variant bits. The same namespace + name always yields the same UUID.
- This page uses the DNS namespace (
6ba7b810-9dad-11d1-80b4-00c04fd430c8) with the nameexample.comby default. You can repurpose the pattern in your own code with any namespace.
How to generate
- Set how many UUIDs you need.
- Toggle uppercase, hyphens and braces as needed.
- Press Generate to compute the deterministic v3 value(s).
Use Cases
- Stable IDs for known entities (e.g. one UUID per domain or per user handle).
- Deduplicating records where the same logical object must always get the same key.
- Cross-system references derived from a canonical name.
How UUID v3 Generator Compares
| UUID v3 | MD5 name-based; deterministic |
| UUID v5 | SHA-1 name-based; deterministic, stronger hash |
| UUID v4 | Random; different every time |
Code Examples
JavaScript
const { v3, v5: ns } = require('uuid');
const id = v3(ns.DNS, 'example.com');Python
import uuid
id = uuid.uuid3(uuid.NAMESPACE_DNS, 'example.com')Frequently Asked Questions
Why is v3 deterministic?
It is a pure function of (namespace, name). The same inputs always produce the same 128-bit output, which is exactly what makes it useful for stable references.
v3 or v5 — which should I use?
Prefer v5: it uses SHA-1 instead of MD5 and is the modern recommendation. Use v3 only for backward compatibility with systems that already expect it.
Can I change the name?
Yes — in your own code pass any name and namespace. The deterministic property holds for whatever pair you choose.