A toxic backlink is a link from a spam or manipulative source. This page lists eight signals that identify one, explains how Google handles spam links, gives a five-step method to find them in your own link export, and states the condition that justifies a disavow file.
What are toxic backlinks?
Toxic backlinks are links from spam or manipulative sources, such as link farms, hacked sites and paid networks. “Toxic” is an SEO-industry term; Google’s own terms are link spam and unnatural links. The term describes link source quality, not a penalty.
A backlink is a hyperlink on one website that points to another. A link farm is a site or group of sites that exists to publish outbound links. A hacked site is a legitimate site whose pages were modified to carry hidden links. Each source type produces links that the target site did not earn and cannot control.
Are toxic backlinks harmful?
Toxic backlinks cause harm only when Google acts on them. Google’s systems nullify unnatural links at scale, so a neutralized link passes no credit and triggers no action. A manual action named “Unnatural links to your site” appears in Search Console when a pattern shows manipulation.
Google’s SpamBrain system identifies spam links at scale and removes their value without notifying the site. A manual action is the rarer case: a human reviewer finds a pattern of links and records the action in the Manual Actions report of Google Search Console. The report names the affected property and the action type.
Third-party tools assign scores to the same links. Moz Spam Score and Semrush Toxicity Score estimate how closely a link source resembles spam. Both are tool estimates and neither shows Google’s view of the link.
What signals mark a backlink as toxic?
Eight signals mark a backlink as toxic: spam anchors, unrelated hosts, link farms, hacked sites, foreign-language networks, deindexed sources, sitewide placements and paid-link footprints. A single signal calls for review; several signals on one link call for removal.
| Signal | Test | Action |
|---|---|---|
| Spam anchors | Anchor text names pharmaceuticals, casino or adult terms unrelated to the site | Remove or disavow |
| Unrelated host | Linking page covers a topic with no connection to the target | Review |
| Link farm | Linking page lists dozens of outbound links to unrelated sites | Remove or disavow |
| Hacked site | Link sits in hidden text or injected content on a legitimate site | Disavow |
| Foreign-language network | Linking pages use a language the site never serves, on many domains with one template | Review, then remove |
| Deindexed source | Linking domain returns no results for a site search | Ignore: the link passes nothing |
| Sitewide placement | One link repeats in the footer or sidebar of thousands of pages | Review |
| Paid-link footprint | Same template, owner or hosting across every linking domain | Remove or disavow |
How do you find toxic backlinks?
Find toxic backlinks in five steps: export links, remove trusted sources, test the remainder against the eight signals, check each source’s indexation and rate the result. Third-party scores supply a first sort, and the eight signals decide each final rating.
- Export all links from Google Search Console and one third-party index.
- Remove links from sources you recognize and trust.
- Test each remaining source against the eight signals in the table.
- Check whether each source page appears in Google’s index.
- Rate each link as Keep, Review or Remove and record the reason.
Run the same seven checks you use for new links, listed in the guide on what makes a link high quality, and treat any link that fails relevance, placement and indexation together as a removal candidate.
When do you disavow a backlink?
Disavow a backlink only when a considerable number of spammy, artificial or low-quality links point at the site and those links have caused, or will likely cause, a manual action. Google describes the disavow tool as an advanced feature.
A disavow file is a plain text file, encoded in UTF-8 or 7-bit ASCII, that lists URLs or domains for Google to ignore. Each line holds one URL, or domain: followed by a domain to cover every link from it. Lines that begin with # are comments.
# Spam network, reviewed 2026-10-11
domain:spam-network-example.com
https://another-example.net/page-with-link.htmlDisavowing a domain that holds good links removes their value, so each entry needs a recorded reason. Links with exact-match anchors from many unrelated sources raise a separate question covered in the guide on exact-match risk.
How do you remove toxic backlinks?
Remove toxic backlinks in three routes, in order: request deletion from the site owner, disavow the domain when no owner responds, and document each attempt. Removal comes first because Google asks for a good-faith effort to remove links before disavowing them.
The disavow service covers sites that need the second route.
Site owners who want a read of their own link set before any removal order a no-cost audit, which includes a backlink profile review.
Related: the backlinks section home and steps after a penalty, and why spam links stay unindexed.