Technical SEO and on-page SEO both affect rankings — but they solve different problems. A technically perfect site with weak content won't rank. A content-rich site with fundamental technical failures won't be indexed. Most sites need both. The right prioritisation depends on the current state of your site.
What is Technical SEO?
What is technical SEO? Technical SEO is the practice of optimising a website's infrastructure so that search engines can efficiently crawl, index, and understand its content. It covers site speed, crawlability, indexation, structured data, URL structure, HTTPS implementation, mobile performance, and Core Web Vitals — everything affecting how search engines access and process your site, rather than what your content says.
Technical SEO problems are foundational. Crawl blocks, noindex tags on important pages, or a broken XML sitemap prevent Google from properly evaluating what you've published. No amount of content investment produces rankings when these issues exist.
What is On-Page SEO?
What is on-page SEO? On-page SEO is the practice of optimising individual pages to communicate their topical relevance, intent match, and quality to search engines. It covers title tags, meta descriptions, heading structure, keyword usage, content depth, internal linking, image alt text, and entity signals — everything within the page itself that influences how search engines evaluate and rank it.
On-page SEO determines whether a technically accessible page ranks for its target queries. A page Google can crawl perfectly still needs strong on-page optimisation to rank competitively.
What Does Technical SEO Include?
Technical SEO covers the infrastructure layer beneath the content.
Crawlability — robots.txt, noindex tags, and server configurations must allow search engines to access every page you want indexed. Important pages blocked by leftover development noindex tags or over-restrictive robots.txt rules appear regularly during technical audits. These are among the most common SEO mistakes found in audits.
Indexation management — submit accurate XML sitemaps, identify and remove duplicate content, and use canonical tags correctly. This ensures Google indexes the right version of each URL.
Site speed and Core Web Vitals — Google's Core Web Vitals (Largest Contentful Paint, Interaction to Next Paint, Cumulative Layout Shift) are ranking signals. Slow sites lose rankings to faster competitors with equivalent content quality.
Structured data — schema markup helps search engines understand content context. It enables rich results (FAQ panels, review stars, product prices) that improve visibility and click-through rates. Entity SEO takes structured data further by establishing your site as a recognised entity in knowledge graphs.
Mobile performance — Google indexes the mobile version of your site first. Pages performing poorly on mobile are evaluated on that performance regardless of desktop experience.
What Does On-Page SEO Include?
On-page SEO covers the content and optimisation layer within each page.
Title tags and meta descriptions — title tags (under 60 characters, primary keyword included) directly influence click-through rates and are a primary relevance signal. Meta descriptions (140–160 characters) influence CTR without directly affecting rankings.
Heading structure — H1, H2, and H3 tags communicate page organisation to search engines. A clear heading hierarchy mirroring the user's question journey performs significantly better than flat or inconsistent heading structures.
Content depth and entity coverage — pages comprehensively addressing their topic, including related entities and subtopics, rank better than narrow pages targeting only the primary keyword. This is the on-page application of topical authority principles, and building topical authority is where content depth compounds into sustained rankings.
Internal linking — links between pages distribute ranking signals and communicate content relationships to search engines. Most sites manage internal linking poorly. My internal linking service addresses this systematically.
Which Should You Prioritise?
Prioritise technical SEO first — always. Fixing crawl and indexation issues produces faster, more reliable improvements than on-page optimisation of pages Google isn't properly evaluating.
Once the technical foundation is sound, on-page optimisation produces compounding returns. More pages become eligible for the rankings they deserve. Run both in parallel where resources allow — fix technical issues whilst improving content quality.
Related Articles
- 9 SEO Mistakes Holding Back Your Rankings — the technical and on-page errors found in most audits
- How to Build Topical Authority — how technical and on-page SEO combine to build authority
- How Long Does SEO Take? — timelines for technical fixes vs content improvements
- Increase Organic Traffic — the complete framework combining both disciplines
My £500 technical SEO audit covers all technical issues with prioritised fix recommendations. On-page optimisation is available per page from £100. Contact me to discuss which your site needs most urgently.