SpamBrain
What is SpamBrain?
SpamBrain is Google’s AI-based spam prevention system. It uses machine learning to detect sites and pages that break Google’s spam policies, including spammy content, sites that buy links and sites used to pass links, so they can be demoted or ignored in search results.
Google first described SpamBrain by name in 2022, in its webspam report, and said it had been using the system since 2018. In the December 2022 link spam update, Google said SpamBrain could now detect both sites buying links and sites used to sell them, and neutralise those links. Google lists it among its spam detection systems and says it improves them over time, with notable changes released as spam updates.
Why SpamBrain matters for SEO
SpamBrain is why black hat SEO has become a worse bet. Spam used to be caught by rules a clever spammer could learn to dodge. A learning system can pick up new patterns, such as a fresh type of PBN or a new kind of scaled content, without anyone writing a rule for it.
It works without notice. If SpamBrain demotes your site or neutralises your links, there is no message in Search Console, only an algorithmic drop. Google says link value lost this way cannot be regained.
How to stay clear of SpamBrain
- Do not buy, sell or swap followed links; label paid placements with rel="sponsored".
- Do not publish content at scale without adding value, whether written by people or AI.
- Keep your site secure so it is not hacked and used to host spam.
- If traffic drops on a spam update date, audit for policy breaches and fix them, then wait for reassessment.
Is Google updating right now? Every confirmed core and spam update, with rollout dates and daily ranking volatility, is on the OpenSEO Google algorithm update tracker.
SpamBrain FAQ
What does SpamBrain detect?
Google says it targets content and behaviour that break its spam policies, including spam sites and link spam. Google does not publish how it works in detail.
Can SpamBrain penalise good sites by mistake?
No system is perfect, but Google’s documentation focuses on spam. If you have done nothing that breaks the policies, a drop is more likely a core update or a technical problem.
Related SEO terms
An algorithmic penalty is a ranking drop caused by Google’s automated systems, not a human reviewer, with no notice in Search Console.
Google’s spam policies list the practices that can get a site demoted or removed from Google Search, from cloaking and link spam to scaled content abuse.
Link schemesBlack hat
A link scheme is any attempt to create links mainly to manipulate rankings, such as buying, swapping or automating links, which is Google’s link spam.
Paid linksBlack hat
Paid links are links bought to pass ranking credit, without rel="sponsored" or nofollow, which breaks Google’s link spam policy.
Scaled content abuseBlack hat
Scaled content abuse is producing many pages mainly to manipulate rankings, with little value for users, whether made by AI, people or both.
A Google algorithm update is a change to how Google ranks results. Big ones, like core and spam updates, are announced and can move rankings sharply.