UUID Namespace

UUID v5 URL Namespace

The URL namespace is the right choice when the thing you are identifying is a web address rather than a bare hostname.

Well-known RFC namespace6ba7b811…Deterministic (SHA-1)

Version

Namespace

Name

How many

Uppercase Hyphens Braces { }

Result

Generated locally with the Web Crypto API — nothing leaves your browser.

What Is UUID v5 URL Namespace?

The URL namespace has the identifier 6ba7b811-9dad-11d1-80b4-00c04fd430c8. It is separate from the DNS namespace so that https://example.com/a and the bare host example.com produce different UUIDs.
Use it when the identity you care about includes scheme, path or query — a canonical page URL, an API endpoint, or an asset address.

How to generate

Select version v5 and the url namespace.
Paste the full URL, including the scheme.
Generate — the same URL always produces the same UUID.

Use Cases

Crawl or cache keys for a URL that must map to one identifier.
Canonical page identity across an index rebuild.
Deduplicating bookmarks or feed entries.

Code Examples

Python

import uuid
uid = uuid.uuid5(uuid.NAMESPACE_URL, 'https://example.com/page')

JavaScript

import { v5 as uuidv5 } from 'uuid';
const id = uuidv5('https://example.com/page', '6ba7b811-9dad-11d1-80b4-00c04fd430c8');

Frequently Asked Questions

Should I normalise the URL first?

Yes. Lowercase the host, drop the fragment, and decide deliberately whether to keep query parameters and a trailing slash — otherwise the same page can hash two ways.

Does the namespace affect the result?

Yes. Identical names under the URL and DNS namespaces give different UUIDs; that separation is the point.