Affiliate Links and SEO: rel="sponsored" and nofollow
Marking links for search engines is a duty separate from disclosing to readers. How to apply rel=sponsored, nofollow, and ugc — and handle link cloaking.
Disclosing an affiliate relationship to your readers is a legal duty. Marking affiliate links for search engines is a separate, technical duty. They are often confused, but they are independent: a legally perfect disclosure does nothing to tell Google a link is paid, and a correctly attributed link does nothing to inform your readers. You must do both.
The link attributes Google recognizes
Google’s Search Central documentation defines three values for the rel attribute on outbound links:
| Attribute | Use | For affiliates |
|---|---|---|
rel="sponsored" | Links that are advertisements or paid placements. | Preferred for affiliate links. |
rel="nofollow" | Links you do not want to endorse or have crawled. | Acceptable for affiliate links; still widely used. |
rel="ugc" | User-generated content such as comments and forum posts. | For affiliate links inside user comments. |
Google’s explicit guidance is to mark affiliate links as sponsored (or nofollow) so they do not pass ranking signals. You may combine values, for example rel="sponsored nofollow".
Why this matters
Passing ranking signals through paid links violates Google’s spam policies on link schemes and can harm your site. Correct attribution keeps you compliant and protects the site’s standing in search.
How to apply it
Add the attribute to the anchor tag: <a href="https://merchant.example/track" rel="sponsored">Product</a>. If you use a link cloaking or redirect plugin, configure it to add the attribute (and typically to route through an internal redirect that is itself disallowed from crawling). Audit periodically, because content pasted from other sources or older posts often lacks the attribute.
Link cloaking and redirects
Many affiliates “cloak” links — routing them through a tidy internal URL such as /go/product that redirects to the affiliate URL. This is acceptable for usability and link management as long as it is not deceptive. Best practice is to block the redirect path in robots.txt and apply the sponsored attribute so search engines understand the links are paid.
The two duties, side by side
| Duty | Audience | Mechanism |
|---|---|---|
| Disclosure | Your readers | Plain-language statement near the link |
| Link attribution | Search engines | rel="sponsored" on the link |
For the disclosure duty, start with the clear-and-conspicuous standard. For content quality, see thin affiliate content and Google’s spam policies.
Authoritative sources
Last reviewed July 2026. This page is general educational information, not legal or tax advice.