What Are Backlinks and Why They Matter for SEO and AI Search

A backlink is a link from another website that points to one of your pages. For Google, it works like a referral: it helps discover the page and, according to Google's own documentation, it is used as a relevance signal. It is not a ranking button: the value depends on who is linking, the context and the topic. In AI search, the effect is indirect and never guaranteed.

Quick summary

A backlink is a link from another site to one of your pages. What matters is where it comes from, the context it appears in and whether it makes sense to the reader.
Google uses links to discover pages and as a relevance signal. Links remain part of its ranking systems, but they are one signal among many.
Quantity is not quality: 10 links from 10 different, relevant sites tend to be worth more than 100 from the same place or from sites with no readers.
There are link types (dofollow, nofollow, sponsored, UGC) and ways to earn them (content, PR, guest posts, mentions, buying). Each has a different risk and effort.
Buying links to manipulate rankings violates Google's spam policies. You can understand the risk and decide knowingly.
For AI, links and mentions help indirectly and without a guarantee. No one outside the AI companies knows the exact weight.

How to read this guide

If SEO is new to you, start with what SEO is and then come back here. Read the sections on the definition, types and the first month, and save the "For SEO professionals" blocks for later. If you already work in SEO, go straight to the sections on signals, quality, measurement and AI. Terms such as DR and referring domain are in the glossary.

This is the central guide on the topic. Each section points to a post that goes deeper, and AI search appears only where it changes things: the full picture is in SEO, AEO and GEO.

What is a backlink?

A backlink (or inbound link) is a link on another page of the internet that leads to a page on your site. When a food blog cites your coffee grind size guide and adds a link, that link is a backlink to your site.

Think of it this way: you need a dentist. A dentist friend recommends a colleague, and another friend, who is not in the field, recommends a clinic because they were treated well. Both referrals count, but not equally. What weighs is who is recommending, whether they understand the subject and whether the referral feels sincere. For Google, backlinks work in a similar way.

In HTML, a link looks like this:

<a href="https://yoursite.com/grind-size-guide" rel="sponsored">coffee grind size guide</a>

Term	What it means	In the example
Source page	The page where the link sits	The food blog post
Source domain (referring domain)	The site that links	The entire food blog
Target page	The page that receives the link	`yoursite.com/grind-size-guide`
Anchor text	The clickable text	"coffee grind size guide"
`rel` attribute	A label that tells Google the nature of the link	`sponsored`
Internal link	A link between pages of the same site	Your post linking to another post of yours

In plain English: a backlink is a door from someone else's house that opens into yours. The busier and more trustworthy the house the door comes from, the more people reach you and the more Google understands that your house is worth a visit.

For SEO professionals: count referring domains, not raw links. Ten backlinks from a single site are, in practice, one repeated recommendation. That is why most studies and tools treat the number of referring domains as the main metric and look at links per page as a detail.

Why do backlinks matter to Google?

They matter because Google uses links for two things: finding new pages and estimating relevance. According to Google's link best practices, links are a signal for determining the relevance of pages and for finding new pages to crawl.

Google's ranking systems guide lists PageRank, which uses links, as one of the core ranking systems that are still active. The same guide mentions systems that understand how pages connect, to decide what they are about and which are most useful. Spam, in turn, is handled by systems such as SpamBrain, which exist to deal with content and behavior that violate the policies.

As for numbers, the Ahrefs study of about 14 billion pages, from December 2023, showed that 96.55% of them get no traffic from Google. Among those that do, pages with more referring domains tend to have more traffic and to rank for more keywords. The authors themselves warn that the sample is biased toward quality content, and a correlation does not prove the link caused the traffic: good pages attract links and traffic.

For SEO professionals: links are a discovery and authority signal, but not the only one. A page with no links and poor content does not rank by magic, and a page with links but no answer to the search intent does not either. On low-competition queries, content and internal linking are usually enough. On competitive queries, the competitors' link profile is what separates page one from page three. See how to compare in the competitor backlink analysis.

What types of backlinks are there?

There are two useful ways to classify them: by the attribute the link carries and by how it came about. The first tells how Google should treat the link, and the second tells how much effort and risk it involves.

By the rel attribute, Google recognizes four situations, detailed in dofollow, nofollow, sponsored and UGC:

Type	When it is used	In short
No attribute (called "dofollow")	An ordinary editorial citation	The default. "Dofollow" is not an official attribute: it is just the popular name
`rel="nofollow"`	When the site does not want to endorse the destination	A hint for Google not to associate the page with the link
`rel="sponsored"`	Paid links and ads	The attribute Google recommends for paid links
`rel="ugc"`	Links posted by users, such as comments and forums	Marks content the site owner did not write

By origin, the most common types are:

Origin	How it arises	Your control	Risk with Google
Natural editorial	Someone cites your content on their own	None	Low
Press mention	An article or note with a link	Low	Low
Guest post	You write an article for another site	Medium	Low to medium, depending on context
Partnership and local directory	Suppliers, associations, chambers of commerce	Medium	Low, if relevant
Comment, forum, profile	You or users post the link	High	Low value, and spam if done at scale
Paid link	Buying a post or a link	High	It exists, and needs to be managed
Blog network (PBN), automated links	Sites built to sell links	High	High. See PBNs and their risks

In plain English: think of the types as word of mouth (editorial), a newspaper note (press), a flyer (directory and comment) and paid advertising (paid link). All of them can bring visits, but only the first group is seen by Google as a spontaneous referral.

What makes a backlink good?

A good backlink comes from a real site on a topic related to yours, inside a text that interests the reader. Authority helps, but it is the easiest characteristic to inflate. The underlying question is simple: would this link exist if no one paid or asked?

Relevance. The topic of the site and the source page relates to yours. A food blog linking to a coffee guide makes sense; the same link on a betting site does not.
Real audience. The site has readers and organic traffic. A site with no visits passes little signal.
Context. The link sits inside the main text, in the middle of a useful sentence, and not in the footer, the sidebar or a "partners" list.
Neighborhood. The source page is not surrounded by links to casinos, adult content or off-topic illegal products.
Naturalness. The anchor text is varied and describes the destination. See anchor text: types, ratios and mistakes.
Diversity. Links come from different sites, over time, without spikes. The natural backlink profile post details this pattern.
Consistent attribute. A paid link must be identified as such (sponsored), as Google asks.

For SEO professionals: DR (Ahrefs), DA (Moz) and similar metrics are third-party estimates, not Google values. They serve to filter, not to decide. Cross-check with estimated organic traffic, outbound link history and the page's own content. The guide how to analyze DA and DR shows the combined reading, and the one on identifying quality backlinks has the full list.

How many backlinks do I need?

It depends on the keyword's competition, and there is no magic number. The most honest method is to compare: see how many referring domains link to the pages that already rank on the first page for your query, and use that as a reference for effort, not as a rigid target. The post how many backlinks do I need shows how to do the math. The effect also takes time: see how long backlinks take to show results.

How do you get backlinks?

There are six paths, from the one that demands the most work of your own to the one that demands the most money. The choice depends on your time, your budget and the size of your site.

Path	How it works	Effort	Who it suits
Linkable content	Original data, guides, tools others want to cite (linkable assets)	High and ongoing	Those with something unique to say
Digital PR	Story angles and data for journalists (digital PR)	High	Brands with news or research
Guest post	Your article on another site (guest posts and outreach)	Medium	Those with expertise and time
Broken links	Offering your content in place of a link that no longer works (broken link building)	Medium	Those who already have equivalent content
Unlinked mentions	Asking for the link from those who already mentioned your brand (brand mentions)	Low	Those who are already cited
Buying links	Paying for a post or a link	Low in time, high in money	Those with a budget who accept the risk

For a local business, the start is usually simpler: backlinks for local businesses and link building for new sites show the first steps.

What does your first month of backlinks look like?

The plan below is a suggestion for beginners. It is meant to build the habit before thinking about volume.

Week 1: see what you already have. Open the Links report in Search Console and note how many domains link to you and to which pages.
Week 2: choose one page. Pick the one that already has impressions and deserves to be cited, and make it excellent (data, direct answer, examples).
Week 3: look for mentions. Search for your brand and product name. Where there is a citation without a link, politely ask for the link.
Week 4: make 5 useful contacts. Suppliers, partners, associations in your industry and blogs that already cover the topic, offering something that helps their readers.
Log everything. A spreadsheet with date, site, URL, anchor and attribute. You will need it later.

Is buying backlinks allowed?

Google does not allow links bought to manipulate rankings, but there is a path within the rules: marking the paid link with rel="sponsored". Google's spam policy defines link spam as creating links to or from a site with the primary purpose of manipulating search results, and includes buying or selling links for that purpose among the examples.

For paid links, Google advises using rel="sponsored" (nofollow is also accepted). That reduces the risk but changes the link's value: a link marked as paid should not pass ranking credit. Part of the value that remains is indirect, such as visits, discovery and brand mentions.

Within that scenario, what changes the risk is quality: relevant context, sites with a real audience, gradual pacing and varied anchors. The details are in is buying backlinks safe?, in the guide to buying quality backlinks and in the checklist before buying. If price is the question, see how much a backlink costs in Brazil.

At Contentor, backlinks are permanent, contextual links on Brazilian, Portuguese-language sites, from a list of more than 4,000 partners (DR 20+). The price is $49 per link in white niches (packages of 1, 3, 5 and 10 links for $49, $147, $245 and $490), with delivery in 7 to 14 business days and free replacement for 6 months. Black niches cost triple. None of this guarantees a Google position, and the policy risk remains.

Do backlinks help you show up in ChatGPT and other AI?

They help indirectly, as far as is known today, and without a guarantee. Public data shows a correlation between links, brand mentions and AI visibility, but no study proves causation, and AI companies do not reveal how they choose sources.

Two documented facts help with the thinking. Google states that there are no additional requirements or special optimizations to appear in its AI answers: the page must be indexed and eligible for a snippet, which depends on SEO basics, including being discovered through links. And OpenAI recommends allowing OAI-SearchBot to appear in ChatGPT search. The rest is hypothesis. The post do backlinks help you appear in ChatGPT? separates evidence from hypothesis, with the studies and their limitations.

In plain English: think of a restaurant that wants to be recommended by a hotel concierge. It does not know the concierge's criteria, but it knows that being known in the neighborhood, having good reviews and being easy to find helps. Backlinks and mentions play that role: they make your brand known and easy to find.

How do you see your site's backlinks?

The free way is the Links report in Search Console. It shows the most linked pages, the sites that link most and the most common anchor texts. The Search Console documentation warns that the tables are limited to 1,000 rows and show a sample of links, and that export reaches 100,000 rows.

In Search Console, open your site's property and click Links.
Under External links, see Top linked pages, Top linking sites and Top linking text.
Export to a spreadsheet and filter the domains you do not recognize.
To see more, use the free tools to analyze backlinks.

Hypothetical example: three links for a specialty coffee shop

The shop "Morning Roast" is fictional, and the links below are there to train your eye.

Link received	How it arose	Attribute	Reading
Citation of the grind size guide in a recipe post on a food blog	Editorial, unrequested	None	Good: relevant, contextual, with readers
Footer link on a generic directory, repeated on 3,000 pages	Automated signup	None	Weak and risky. Do not count on it
Comment on a food blog with the shop's link	Posted by a user	`ugc` and `nofollow`	Little ranking value, may bring a visit. Correct markup
A local news site cites the shop in a piece about coffee shops, without a link	Mention	No link	Opportunity: ask for the link politely

In two practical decisions: strengthen the relationship with the food blog (a second joint piece of content) and write to the news site asking that the shop's name link to the site. The directory does not deserve time.

What mistakes do beginners make most with backlinks?

Counting links instead of sites. Fifty links from the same domain count for little.
Trusting DR alone. The metric does not see whether the site has readers.
Repeating the same commercial anchor. It looks like manipulation.
Buying cheap volume. Automated packages can cost more than they are worth and attract a penalty. See penalties for artificial links and disavow.
Expecting results in days. Google needs to crawl and reassess.
Ignoring the content. A link speeds up pages that already deserve to rank; it does not save thin text. If content is your bottleneck, generating articles with AI on Contentor and reviewing them with your own experience is one path.

Frequently asked questions

What is a backlink in simple words?

It is a link from another site that leads to a page of yours. It works like a referral: the more relevant and trustworthy the one referring, the more the link helps Google understand that your page deserves to be read. The value depends on context, topic and the quality of the source site.

Do backlinks still work in 2026?

Yes, in the sense that Google states it still uses links as a signal and that PageRank remains among its core systems. That does not mean more links guarantee a position: the effect depends on competition, content and link quality, and it is one signal among many.

What is the difference between a backlink and an internal link?

A backlink comes from another site and points to yours. An internal link connects pages on the same site. Both help Google discover pages and understand what they are about, but only backlinks work as an external referral. For internal links, see the internal linking guide.

Is dofollow better than nofollow?

For ranking, links with no attribute are usually treated as the most useful, but Google treats nofollow, sponsored and ugc as hints, not commands. A natural profile mixes types, and links with an attribute can bring visits and mentions. The useful question is not which is better, but whether the attribute matches the nature of the link.

Can I have a site with no backlinks at all?

You can, but discovery and authority get harder, especially on competitive queries. Google also discovers pages through a sitemap, and on low-competition queries content may be enough. The decision to invest in links should come from the real competition for your keyword.

Is buying backlinks risky?

It carries risk, and it is not zero: Google considers buying links to manipulate rankings a violation. The risk drops with contextual links, on sites with a real audience, at a gradual pace and with varied anchors, but it still exists. Read is buying backlinks safe? before deciding.

Next step

Now that you know what a backlink is, the next step is understanding how Google reads each type of link: start with dofollow, nofollow, sponsored and UGC, then move on to anchor text. If the question is how many you need, go to how many backlinks do I need.