What are the types of SEO? From On-Page to SEO for AI

Searching on Google has stopped being the only path to a website. People ask ChatGPT, request recommendations from Gemini and receive ready-made answers at the top of search itself. Even so, organic search remains the most consistent entry point for qualified visitors to most sites.

In that scenario, understanding the types of SEO has stopped being glossary trivia. Each pillar answers for part of the result, and the strategy only works when they operate together, in the right order and with the right weight for the moment the business is in.

This guide runs through the four classic pillars and the new layers created for AI search. The aim is to explain what each type covers, when it becomes a priority and how to apply all of it without multiplying acronyms, effort and budget.

What is SEO and why does it split into types?

SEO is the set of practices that improves a site's position in search engines' organic results. It splits into types because ranking depends on factors of different natures: the page's content, the domain's authority, the site's technical health and the local context of whoever is searching.

Caption: the types of SEO are not competing fronts: content, authority, technical base, local context and the AI layer accumulate on the same site

That division organises the work, but it does not create rigid borders. A 2019 BrightEdge study that became a reference found that around 53% of trackable website traffic comes from organic search, which explains why so many fronts compete for space inside the same strategy.

Every type of SEO starts from the same search essentials: useful content made for people, pages accessible to crawling and no attempt to manipulate ranking. The pillars are different routes to meeting those same rules.

Day to day, the most consistent SEO strategies distribute effort across the pillars according to the site's stage, instead of betting everything on one front. A new site has different bottlenecks from a blog with ten years of published content.

What is On-Page SEO and what does it optimise?

On-Page SEO is the type of SEO that works inside the page: title, meta description, subheadings, keywords, content quality, internal links and images. The goal is to make clear, to people and to robots, which question that page answers and why it deserves the position it is competing for.

The starting point is search intent. A page that answers exactly what the person meant to ask tends to hold more readers, and that retention sends positive signals back to the search engine. A keyword in the title, in the first paragraph and in the subheadings helps, as long as the reading stays natural.

Internal links complete the work inside the page. They connect content on the same theme, distribute authority across the site's pages and show the search engine which ones are the most important in each topic group.

Images also belong to this front. Descriptive file names, alt text that explains the scene and proper compression improve accessibility, open space in image search and reduce the page's weight.

The content itself weighs more than any isolated tweak. Criteria of experience, expertise, authoritativeness and trust, gathered in the concept of E-E-A-T, guide quality assessment and apply to every type of SEO, not just On-Page.

How does Off-Page SEO build authority?

Off-Page SEO is the type of SEO that happens outside the site: backlinks, brand mentions, reviews and digital public relations. It builds authority because every link from a trustworthy site works as a vote of confidence, and domains with more qualified votes tend to rank better.

Quality matters more than volume. A link from a respected outlet in your sector is worth more than dozens of links from generic sites, and schemes to buy or trade links violate search engine rules, with a real risk of penalty.

The tactics that work best create value before asking for anything in return: producing original research and data other sites want to cite, taking part in sector outlets as a source and keeping public profiles consistent. Mentions without a link count, because they reinforce the brand as an entity.

Video: the techniques that build authority outside the site, one of the types of SEO, on the mkt4edu channel (video in Portuguese)

What does Technical SEO cover and why does it come first?

Technical SEO is the type of SEO that makes sure the site can be crawled, indexed and loaded quickly. It covers architecture, sitemap, robots.txt, speed, the HTTPS security certificate, structured data and the experience on mobile devices. Without that base, the other types of SEO work in a vacuum.

The reasoning is direct: the search engine has to find the page, understand what it contains and deliver it quickly to whoever is searching. Crawl errors, orphan pages and extreme slowness do not bring down just one page, they shorten the reach of the whole site.

Being mobile-friendly became a prerequisite, not a differentiator. Google uses the mobile version of the content to index and rank pages, so a site whose mobile version hides part of the content delivers less material to the index than it thinks. The recommendation is to keep parity between mobile and desktop content.

Structured data closes the technical front. Markup such as Article and BreadcrumbList helps search engines understand the page's context, keeps generating visual results in search and feeds the systems that assemble AI answers.

When does Local SEO make a difference in recruitment?

Local SEO is the type of SEO aimed at searches with geographic intent, such as "business degree near me". It makes a difference whenever the business depends on a physical presence or serves a defined region, because those searches trigger Google's local pack, with a map, reviews and contact details.

The centre of this front is the Google Business Profile. The right category, a consistent address, updated hours, real photos and replies to reviews all weigh on local ranking, and consistency of name, address and phone across directories reinforces trust in the brand.

Reviews deserve a routine of their own. Volume, average score and recency influence both ranking and the decision of someone comparing options, and polite replies to public criticism build trust with those still evaluating.

For the education sector, this front is usually decisive: choosing an institution almost always starts with a regional search, and local SEO for colleges has its own dynamic, with maps and AI answers entering the decision journey.

What is SEO for AI: AEO, GEO and SEO for LLM?

SEO for AI is the set of practices that increases the chance of a brand being cited in AI-generated answers, such as AI Overviews, ChatGPT and Gemini. The acronyms AEO, GEO and SEO for LLM describe emphases of that same work, each one looking at a type of answer engine.

The AEO front structures content so it is easy to extract: a direct answer at the top of each section, self-contained paragraphs and headings written the way people actually ask.

GEO looks at generative engines. Researchers from Princeton and other institutions measured, in the study GEO: Generative Engine Optimization, the tactics that most raise a site's visibility in generated answers, with gains of up to 40%: citing named sources, including expert quotes and bringing verifiable statistics.

SEO for LLM extends the same logic to language models consulted outside search, such as assistants and AI agents. The path to being cited by AIs runs through content accessible to those platforms' crawlers, clear data and a brand consistently associated with the topic.

None of that replaces the base. There is no additional requirement to appear in AI Overviews or AI Mode: the same practices as traditional search SEO apply, with the important content available as text and crawling allowed. The borders between SEO, AEO and GEO help decide where to invest first.

The effort pays off: a Semrush survey indicates that visitors from AI searches convert 4.4 times better than those from traditional organic search, a sign that this audience arrives closer to the decision. It is a market survey, with no sample or period published in the article, and not an official platform statement.

SXO and AIO: what do those acronyms change in SEO?

SXO and AIO are recent labels for concerns that already live inside SEO. SXO adds user experience to search optimisation, measuring what happens after the click. AIO is usually used as an umbrella for optimisation aimed at AI systems in general.

In practice, SXO joins SEO, UX (User Experience) and CRO (Conversion Rate Optimization): attracting the click is half the work, and the other half is turning the visit into an action, with fast pages, clear navigation and well-placed calls to action.

Video: how CRO, SEO and UX combine in the experience layer of the types of SEO, on the mkt4edu channel (video in Portuguese)

AIO still has no stable market definition: some use it as a synonym for SEO for AI and others extend it to the use of AI inside the marketing operation itself. Rather than fighting over acronyms, it is worth treating those layers as lenses on the same principle, which is delivering trustworthy content with a good experience.

How do you apply the types of SEO in practice?

Applying SEO in practice means sequencing the fronts according to the site's maturity: first the technical base, then On-Page content, then Off-Page authority, with Local SEO and the AI layers entering according to the business model. No type replaces another, they accumulate.

Each front has a clear priority trigger, and seeing the types side by side makes it easier to decide where to invest the next cycle:

Table: the four pillars and the AI layer among the types of SEO, with the symptom that indicates where to invest first

The order suggests a path, not a queue. A site can fix the technical base and produce content at the same time, as long as there is clarity about which front unlocks the results of the others at that moment.

Measuring closes the cycle. Organic traffic, positions, conversions and citations in AI answers together tell the story of the investment, and the calculation of SEO's return becomes more honest when each front has its own metric.

Video: six practical tips that cut across the types of SEO, from the technical base to content, on the mkt4edu channel (video in Portuguese)

Frequently asked questions about the types of SEO

How do you turn the types of SEO into qualified traffic?

Turning the types of SEO into qualified traffic is a matter of sequence and consistency: a healthy technical base, content that answers real search intent, authority built patiently and presence in AI answers. Treating the fronts as a single system yields more than chasing each acronym on its own.

The diagnosis comes before the investment. Understanding which pillar is blocking growth avoids spending months optimising content on a site with indexing problems, or building backlinks to pages that do not convert.

If you want that diagnosis with specialist support, the SEO team at mkt4edu works all those fronts in an integrated way, from the technical base to SEO for AI. Let's talk about where your site stands.