SEO vs AEO vs AIO vs GEO: What's the Difference?

Search has quietly split into four separate disciplines, and most of the confusion comes from treating them as one thing. Here's what each acronym actually measures.

SEO: can a search engine rank your page

Classic technical SEO covers the fundamentals: meta tags, heading structure, word count, and the kind of on-page issues that have mattered since search engines started crawling the web. This is the foundation everything else builds on. A page with broken fundamentals won't get far no matter how well it's optimized for AI.

AIO: can an AI crawler even read your page

Before any answer engine or generative model can consider citing your content, its crawler has to actually reach it. AIO checks whether robots.txt is blocking bots like GPTBot or ClaudeBot, whether a /llms.txt file exists to guide AI agents to your key content, and whether your heading hierarchy is clean enough for a machine to parse the page's structure correctly. This is access, not persuasion. A page can be blocked from AI crawlers entirely and never even enter the running.

AEO: can you be picked as the direct answer

Once a page is reachable, AEO measures whether it's structured to be selected as a direct answer, the kind that shows up in Google's AI Overviews or gets read aloud by a voice assistant. This comes down to FAQPage schema, question-style headings, and HowTo markup for step-by-step content.

GEO: will a generative engine cite you

GEO measures citation readiness for generative engines like ChatGPT and Perplexity, the kind that synthesize a longer answer and credit a source. This depends on author credibility signals, concrete data and statistics, and scannable formatting like lists and tables.

Why you need all four, not just one

These four checks build on each other. Solid technical SEO is the base. AIO makes sure AI systems can actually reach that base. AEO and GEO then determine whether they choose to feature or cite what they find. Optimizing for only one leaves real visibility on the table.

Verolyx scores every crawled page across all four pillars in a single free audit, then generates an AI-written content, campaign, and 90-day roadmap plan from the results. Run an audit to see exactly where your site stands on each one.