Avoiding Duplicate-Content SEO in Custom Portals

Note: This guidance does not require any changes to the Walrus Sites portal itself. It is focused on site-level fixes (HTML tags or HTTP headers) that developers can add when hosting their own portals.

When you deploy your own Walrus Sites portal, you may expose the same site under multiple hostnames:

  • SuiNS – human-readable names registered on-chain, e.g. snowreads.wal.app.
  • Base36 – subdomains derived directly from the site object ID, e.g. 1myb…xd.portal.com.
  • Custom domains – BYOD, e.g. example.com.

Search engines treat the same content served at multiple hosts as duplicates, which can dilute ranking signals.

The official wal.app portal avoids this issue by only serving SuiNS domains, with base36 and BYOD disabled. If you run your own portal and enable base36 or BYOD, you must take steps to signal a canonical host.

Example Scenario

Problem: You run a site that is reachable at both:

  • https://example.wal.app/math (SuiNS)
  • https://example.com/math (Custom domain)

A web crawler will see identical content at two different URLs and may treat them as duplicates.

Solution: Add a canonical hint so crawlers know which host to index:

In the HTML <head>:

<link rel="canonical" href="https://example.com/math" />

  • Canonical host policy Choose one hostname type per site (custom domain > SuiNS > base36 is a good priority). All other hosts should include canonical hints pointing to that choice.

  • Base36 subdomains

    • Disable if not needed: B36_DOMAIN_RESOLUTION_SUPPORT=false.

    • If enabled, add canonical hints (<link rel="canonical"> or Link: rel="canonical").

    • Optionally, block them from indexing with:

      X-Robots-Tag: noindex

  • Custom domains

    • Setting BRING_YOUR_OWN_DOMAIN=true makes the portal serve only your configured custom domain (single-site mode). Other domains, including SuiNS and base36, are not resolved by that portal.
    • It’s always a good practice to add canonical hints in your HTML or headers pointing to your chosen custom domain, to avoid duplicate indexing across different hosts.

  • Multiple SuiNS names → one site This can happen permissionlessly. If you own the extra names, add canonical hints in your site HTML to point to your preferred domain.