Types of SEO: 7 Kinds Plus the New AI Layer

The main types of SEO are technical SEO, on-page SEO and off-page SEO. Content, local, ecommerce and international SEO are those three applied to a specific job, and the newest layer, AI search optimization (often called AEO or GEO), sits on top of all of them. Lists of “12 types” or “21 types of SEO” mostly split the same work into smaller labels.

This guide is for owners and marketers deciding what to hire for or what to do first. It explains each type in a paragraph, shows which part of your business each one touches, and ends with a short decision tree for picking the ones that apply to you. If you only need the definition of the acronym, start with what does SEO stand for.

On this page

• How many types of SEO are there?
• The three core types of SEO
• Local, ecommerce and international SEO
• Is content SEO a separate type?
• The AI search layer
• Who does each type of SEO
• Which type of SEO should you start with?

How many types of SEO are there?

There are three core types, and everything else is a context. That is a more useful answer than a long list, because it tells you what depends on what. The layered model below shows the idea: technical SEO is the floor, on-page and content work sit on it, off-page reputation sits on that, and AI visibility is the top layer that only holds if the rest does. Local, ecommerce and international SEO change the details at every layer without adding a new one.

The three core types of SEO

Every website needs all three, in this order of dependency.

Technical SEO

Technical SEO makes sure search engines can reach, render and store your pages. Google’s minimum technical requirements are that Googlebot isn’t blocked, the page returns an HTTP 200 status, and it has indexable content. Google adds that meeting those requirements doesn’t guarantee indexing. In practice the work covers robots.txt, XML sitemaps, canonical tags, redirects, page speed, mobile rendering and JavaScript. Speed has published targets: Google’s Web Vitals guidance calls a page good when its largest content loads within 2.5 seconds and it responds to interactions in 200 ms or less. It is usually a developer’s job, guided by an SEO. Our technical SEO checklist lists the checks, including the ones AI crawlers add.

On-page SEO

On-page SEO makes each page clearly and usefully about one thing. It covers the title, headings, body copy, images, internal links and structured data. Google’s SEO Starter Guide is blunt about what doesn’t matter here: it says there’s no magical word count, heading order doesn’t matter, and keywords in the domain name have hardly any effect. The work is writing and editing more than configuration. Our on-page SEO checklist turns it into roughly 30 checks.

Off-page SEO

Off-page SEO builds the reputation other sites give you: links, reviews, press, directory listings and unlinked mentions. Links still count because Google lists PageRank among its core systems in its ranking systems guide. The risk is also here: Google’s spam policies name buying links, excessive link exchanges and automated link building as link spam. What are backlinks explains which links help and which ones hurt.

Local, ecommerce and international SEO

These three are the core types applied to a specific business model. Each adds its own tools and its own failure modes.

Local SEO is for businesses customers find by place: dentists, plumbers, restaurants, law firms. Google’s Business Profile help names three local ranking factors: relevance, distance and prominence, and states that there’s no way to request or pay for a better local ranking. Prominence includes links and reviews, so local SEO leans hard on off-page work, and customers check the same reviews: BrightLocal’s 2026 survey found 97% of consumers read reviews for local businesses. Our local SEO checklist has 35 steps.

Ecommerce SEO is for stores. Google’s ecommerce guidance covers sharing product data with Google, product structured data, URL structure, navigation and pagination. The distinctive problems are scale: thousands of near-identical product pages, filter combinations that create endless URLs, and out-of-stock pages. See ecommerce SEO for the playbook.

International SEO is for sites serving several languages or countries. The core tool is hreflang, which tells Google that pages are localized versions of the same content. Google’s rule is strict: each version must list itself and every other version, and if two pages don’t point to each other, the tags are ignored. Our hreflang guide covers setup.

Is content SEO a separate type?

Content SEO is the planning half of on-page SEO, and it earns its own name because it is where most of the budget goes. On-page work optimizes a page that exists. Content work decides which pages should exist: which questions to answer, how to group them into clusters, and which old pages to merge or retire.

It starts with keyword research and ends with a brief a writer can follow. Two parts matter more now than they did five years ago:

• Answer placement. Google’s ranking systems include passage ranking, which identifies individual sections of a page to judge relevance. A section that answers its question in the first sentence is easier to match and easier to quote.
• Coverage over repetition. AI systems split one question into several related searches, which Google’s AI features documentation calls query fan-out. A cluster of pages that answer the follow-up questions has more chances to be picked up than one page repeating a keyword.

The AI search layer

The newest type is not a new discipline but a new outcome: being named, cited or recommended in AI answers from Google AI Overviews and AI Mode, ChatGPT, Gemini and Perplexity. Google says there are no additional requirements for its AI features beyond being indexed and eligible for a snippet. Microsoft’s Bing Webmaster Guidelines say SEO fundamentals still apply to grounding and AI experiences. The layer changes what a ranking is worth: in Pew Research Center’s March 2025 study, Google users who saw an AI summary clicked a traditional result in 8% of visits, against 15% when no summary appeared, and clicked a link inside the summary in just 1%.

What shifts is the weighting between the layers. In an Ahrefs study of 75,000 brands, branded web mentions correlated with AI Overview visibility at 0.664, against 0.218 for the number of backlinks, and roughly 26% of those brands had no AI Overview mentions at all. That pushes off-page work from “earn links” toward “be talked about”, including unlinked mentions. We compare the labels people use for this layer in AEO vs GEO vs SEO.

Other types of SEO you will see listed

Longer lists add labels that are real tasks but not separate disciplines. Here is where each one actually belongs:

• Mobile SEO is technical SEO. Google has indexed the mobile version of pages first since it moved to mobile-first indexing, so there is no separate mobile ranking to chase.
• Image and video SEO are on-page SEO for media: descriptive file names, alt text, and standard HTML image elements. Google’s image guidance notes that it doesn’t index CSS background images. YouTube SEO is closer to a separate channel, because YouTube has its own search.
• Voice SEO is content SEO with shorter, spoken-style answers. The underlying results come from the same index.
• White hat and black hat SEO are not types but a line between methods that follow the spam policies and methods that break them. Black hat tactics can work briefly; the policies say violating sites may rank lower or not appear at all.
• Negative SEO means attempts to harm a competitor, usually with spammy links pointed at their site. It is a risk to monitor, not a service to buy.

The labels matter only when you are reading a proposal. If an agency prices “voice SEO” as a separate line item, ask which pages and which tasks it changes that the content plan does not already cover.

Who does each type of SEO

The matrix below maps each type to the part of the business it touches. Filled dots mark the main area, hollow dots a secondary one. It explains why SEO rarely belongs to one person: technical work sits with developers, content with writers, and off-page work with whoever owns PR and partnerships.

The same split as a table, with the typical owner and the first sign you need it:

Which type of SEO should you start with?

Start with technical SEO, then add only the contexts that match your business. The decision tree below is the short version. Almost every site ends in the same place: the three core types, checked against how AI answers describe you.

A practical order for most small and mid-sized businesses:

1. Fix technical blockers. Check Search Console for pages that are not indexed and why.
2. Fix on-page basics on the pages that make money. Service, product and location pages before the blog.
3. Fill content gaps. Write the pages customers ask about that do not exist yet.
4. Build reputation. Reviews, directory listings, partner mentions, press.
5. Check AI answers. Ask ChatGPT, Gemini and Perplexity the questions your customers ask and note who they name.

Getting the types of SEO working together

The types only split cleanly on paper. A slow template (technical) hurts a well-written page (on-page), and a strong page with no reputation (off-page) loses to a weaker page from a better-known site. The AI layer makes the coupling tighter, because an assistant decides what to say using all three at once: whether it can read the page, whether the page answers the question, and whether other sources agree with it. The mechanics of that pipeline are covered in how does SEO work.

If you are deciding what to hand to whom, the table above is a reasonable starting brief. If you would rather have one team run all three core types with the AI layer measured from the start, that is what our AI SEO service covers.