The difference at a glance
The labels describe where the work happens. On-page work changes the page itself. Off-page work changes how the rest of the web relates to you. Technical work changes how the site is built and served, so that search engines can process the pages at all. The split is useful because each area has a different owner, a different pace and a different kind of risk.
| On-page SEO | Off-page SEO | Technical SEO | |
|---|---|---|---|
| Core question | Is this page the most useful answer to the search? | Do others vouch for this site? | Can search engines crawl, render and index it? |
| Typical elements | Content, title, H1, headings, internal links, images, structured data | Links from other sites, brand mentions, reviews, press coverage | Site speed, indexing rules, redirects, canonicals, sitemaps, mobile rendering |
| Who usually does it | Writers, subject experts, SEO | Marketing, PR, partnerships | Developers, technical SEO |
| Control | Full | Partial: you influence, others decide | Full, within the platform's limits |
| Speed of effect | Often weeks after recrawling | Months, gradually | Fast once fixed, if it was a real blocker |
| Main risk | Writing for a keyword instead of a reader | Manipulative link schemes that breach Google's policies | Changes that accidentally remove pages from the index |
What on-page SEO means
On-page SEO, sometimes written as on-page search engine optimisation or simply SEO on page, is the work of making a single page the clearest, most complete and most trustworthy answer to the search it is meant for. It covers what the page says and how that is signalled to search engines.
The most important on-page factor is not a tag at all. It is whether the content matches the intent behind the search. Someone typing 'electrician Croydon' wants to find and contact an electrician, not read a history of electrical regulations. Someone typing 'how to reset a tripped fuse box' wants instructions. Get the intent wrong and no amount of tag optimisation will compensate.
Google's SEO Starter Guide describes most of the on-page basics in its own words, and it is worth reading once from start to finish.
The on-page elements, one by one
Work through these for each important page. Each serves the reader first and the search engine second.
- Title. The main clue to what the page is about and the text most likely to appear as the clickable headline in results. Make it unique, put the topic early and write it for humans. Google explains how it chooses title links, which are sometimes rewritten when the title is vague or stuffed.
- H1 and headings. One main heading that confirms the topic, then subheadings that follow the questions the reader has, in the order they have them.
- Opening paragraph. Answers the main question directly. This helps readers, featured snippets and AI summaries alike.
- Body content. Complete enough that the reader does not need to go back to the results. Specific details, examples and honest trade-offs are what separate an expert page from a generic one.
- Internal links. Links to and from related pages, with anchor text that describes the destination. They help visitors and show search engines how your pages relate.
- Images. Real photographs where possible, compressed for speed, with descriptive alt text for meaningful images.
- URL. Short and readable, describing the topic.
- Meta description. Not a ranking factor in itself, but often used as the snippet below the title, so it affects whether people click. See Google's guidance on snippets.
- Structured data. Code that describes the page content (an article, a product, a business) in a format machines read reliably, which can make a page eligible for richer results.
On-page content writing is a craft in itself; our guide on how to write SEO content covers the writing process in detail.
On-page mistakes we see often
- Two pages chasing the same search. A service page and a blog post both aimed at 'office cleaning Leeds' compete with each other. Decide which one owns the search and point the other to it.
- Titles written for a tool. 'Plumber London | Plumbing London | Emergency Plumber London' reads as spam to a person and is likely to be rewritten by Google.
- Thin location pages. Dozens of pages where only the town name changes add nothing for readers and can count as doorway pages under Google's policies.
- The answer buried at the bottom. Four paragraphs of introduction before the reader learns anything.
- Text inside images. Prices, services or opening hours shown only in a graphic cannot be read reliably by search engines or screen readers.
- No internal links into the page. A new page that nothing links to is hard to discover and looks unimportant.
What off-page SEO means
Off-page SEO covers the signals about your site that come from outside it. Its core is links: when a relevant, reputable site links to a page, that is a vote of confidence that search engines can take into account. Google's own guidance on links states that it uses links both to find new pages and as a signal when judging how relevant a page is.
Off-page SEO also includes:
- Brand mentions in trade press, local news, podcasts and industry directories, even without a link.
- Reviews on Google and on sector platforms, which matter particularly for local results.
- Consistent business details across directories, which help confirm who and where you are.
- Digital PR: creating something newsworthy (data, research, expert commentary) that journalists want to reference.
For local businesses, the Google Business Profile is the most visible off-page asset; our Google Business Profile guide covers it in full.
Building authority without taking risks
Off-page work is where the most damaging shortcuts are sold. Google's spam policies name link schemes explicitly: buying or selling links that pass ranking credit, excessive link exchanges, large-scale guest posting with keyword-rich links and automated link creation. Links that are paid for, such as sponsorships or adverts, should carry the appropriate rel attribute.
Safe off-page work looks unremarkable from the outside because it is the normal business of being known:
- Ask suppliers, partners and trade bodies you genuinely work with whether they list members or partners.
- Offer expert comment to journalists covering your sector.
- Publish something worth citing: original figures, a clear explainer, a useful calculator.
- Take part in your local business community, and let that be reflected online.
It is slower than buying links, and that is the point: it builds something a competitor cannot replicate overnight. Our page on link building explains how we approach it.
Where technical SEO fits
On-page and off-page work both assume the page can be found and indexed. Technical SEO makes sure it can. If Google cannot crawl a page because of a robots rule, a stray noindex tag, a broken redirect or content that only appears after complex scripts run, the finest writing and the strongest links achieve nothing.
Some elements sit on the border. Page speed affects how the page feels to read, so it touches on-page experience, but fixing it is usually technical. Structured data lives on the page but is implemented in code. Do not worry about the labels; worry about whether someone owns each task. Our page on technical SEO covers the foundation in detail.
On-page SEO tools and checkers: what they catch and what they miss
There are many on-page SEO checkers and analysis tools, from free browser extensions to full software suites. They are good at mechanical checks:
- missing, duplicate or overly long titles and descriptions;
- missing H1s or several competing ones;
- images without alt text, oversized images;
- broken links, redirect chains, missing canonical tags;
- slow pages, using lab data from tools such as PageSpeed Insights.
What no tool can judge is whether the page actually answers the search better than the alternatives, whether the advice is accurate, or whether a reader would trust it. Tools that score 'keyword density' or demand a fixed word count encourage writing for the tool rather than the reader. Use checkers to find mechanical faults quickly, then let a person who understands the customer judge the content.
The same caution applies to AI writing assistants used for on-page work. Google's position on generative AI content is that the method matters less than the result: content created primarily to manipulate rankings breaches its policies whatever the tool, while genuinely helpful content can perform. Accuracy and real expertise remain the author's responsibility.
Which to work on first
For most businesses, the order is: technical blockers first, on-page second, off-page alongside and ongoing.
- Fix anything that stops indexing. It is usually quick and nothing else works until it is done.
- Improve your most valuable pages on-page. You control it fully, and it often produces visible movement within weeks of recrawling.
- Build authority steadily. It compounds slowly, so start early, but do not expect links to rescue a page that does not answer the search.
The exception is a site that already has excellent pages but competes against much stronger sites. There, off-page work deserves more of the effort. Our SEO checklist can help you see which situation you are in.