Technical SEO guide

What is technical SEO?

Technical SEO is the work of making a website easy for search engines to crawl, render, index and understand, covering site structure, speed, security and code rather than content or links. If search engines cannot reach or interpret a page, good writing on it will not be found.

Examples include a clean URL structure, an XML sitemap, fast-loading pages, HTTPS, and structured data that labels what a page is about. Our Core Web Vitals article covers the speed side in detail.

Technical SEO versus on-page and off-page SEO: the three areas answer different questions, and each depends on the others.

Technical SEO does not cover writing content, earning backlinks or running paid ads. It also cannot make weak content rank; it removes barriers so good content gets a fair chance. For the wider picture, see our SEO services.

Why does technical SEO matter for your business?

Technical SEO matters because pages that search engines cannot crawl, render or index cannot appear in results, no matter how good the content is. Content, links and brand work only pay off once the site underneath lets search engines reach and understand each page.

For a business, technical faults can quietly waste money already spent on copywriting, design and promotion. Our SEO services start from this foundation for that reason.

How technical faults hide good content: they block, slow or confuse the systems that read your pages. Common examples include:

• A stray noindex tag or robots.txt rule that blocks key pages
• Content that loads only through JavaScript that crawlers fail to render
• Duplicate URLs that split signals between near-identical pages
• Slow or unstable pages, which Core Web Vitals measures
• Broken redirects or long redirect chains that waste crawl effort

When technical problems usually appear: at moments of change, such as a redesign, a platform migration, a URL restructure, or a plugin or template update. They also build up slowly on large sites as old pages, filters and redirects pile up.

Platform choice can add risk too, as our comparison of Wix vs WordPress SEO shows. A regular check catches these issues before they cost visibility.

How do search engines crawl, render and index a website?

Search engines discover pages by following links and sitemaps, render them to see the content, then decide which version to store in their index. Each stage can fail separately, so a page can be crawled but never indexed.

Crawling is the stage where a bot, such as Googlebot, requests your URLs. Crawl budget is the number of URLs a search engine is willing and able to fetch from your site in a given period. Small sites rarely hit limits, but large sites with filters, duplicate URLs or slow servers can waste budget on pages that do not matter.

Rendering is the stage where the search engine runs your page's code to build what a visitor sees. If key text, links or product details only appear after JavaScript runs, they may be picked up later or missed. Server-side rendering or pre-rendering important content reduces that risk.

Indexing is the stage where the search engine analyses the rendered page and stores it for retrieval. When several URLs show near-identical content, the canonical tag (a line of code naming the preferred URL) tells search engines which one to keep. Redirects, internal links and sitemaps should point to the same preferred version.

• Crawl: check robots.txt, internal links and XML sitemaps.
• Render: confirm important content appears in the rendered HTML.
• Index: review canonical tags, noindex directives and duplicate URLs.

Our SEO services start with a site audit that checks each of these three stages.

What are the main parts of technical SEO?

The main parts are crawlability, indexability, site architecture, page speed, mobile usability, security and structured data, and each can be checked separately. Crawlability and indexability decide whether search engines can reach and store your pages. The other parts shape how well those pages work once found.

Site architecture and internal linking. Site architecture is how your pages are grouped and connected. A clear structure, short click paths from the homepage and descriptive internal links help crawlers find important pages and show which ones matter most.

Page speed and Core Web Vitals. Core Web Vitals are Google's measures of loading, responsiveness and visual stability. Slow templates, heavy images and bloated scripts are common causes of poor scores. See our guide to Core Web Vitals for detail.

Mobile usability and HTTPS. Mobile usability means pages read and work properly on a phone, since Google mostly indexes the mobile version. HTTPS encrypts the connection, and mixed content or bad redirects can undermine it.

Structured data. Structured data is code, usually schema markup, that labels things like products, reviews, FAQs and business details. Search engines can use it to understand a page and sometimes show richer results, though display is never guaranteed.

Our team covers these checks as part of our SEO services, starting with a site audit.

Which technical SEO fixes should you do first?

Fix problems that block crawling or indexing first, then duplicate content and speed issues, then refinements such as structured data, ranked by impact against effort. A page that search engines cannot reach or store cannot appear in results, so no other improvement helps it.

To rank fixes, score each issue for impact (how many important pages it affects) and effort (developer time and risk). Start with high-impact, low-effort items, then schedule high-impact, high-effort work.

• Do first: indexing blocks and sitemap errors.
• Do next: errors, duplicates and redirects.
• Plan: speed and template changes.
• Finish with: structured data and other refinements.

Our SEO services begin with a site audit and an agreed work plan, so fixes follow this order before any change goes live.

How do you run a technical SEO audit?

A technical SEO audit follows a repeatable sequence: crawl the site, review index coverage, check redirects and canonicals, test speed and mobile, validate structured data, then prioritise fixes. Working in the same order each time makes one audit comparable with the next.

1. Crawl the site with an SEO crawler and list broken links, error pages, duplicate titles and blocked URLs.
2. Review index coverage in Google Search Console and compare indexed pages with the pages you want found.
3. Check redirects and canonicals: remove redirect chains and confirm each page points to the right preferred URL.
4. Validate the XML sitemap: it should list only live, indexable, canonical URLs and be submitted to search engines.
5. Test speed, including Core Web Vitals, on your key templates.
6. Test mobile usability on real devices and check that content matches the desktop version.
7. Validate structured data and fix errors or markup that does not match visible content.
8. Prioritise fixes by impact and effort, then assign owners and dates.

How often to repeat the audit depends on how much your site changes. A full audit once or twice a year suits a stable site. Sites that publish often, run a store or are migrating should add lighter monthly checks of crawl errors and indexing.

If you want a specialist to run the audit, our SEO services begin with a site audit, and you can contact us to discuss scope.

How long does technical SEO take and what does it cost?

Time and cost depend on site size, platform, the number of issues found and how quickly developers can ship fixes, so a scoped audit is the reliable way to get an estimate. A figure quoted before anyone has crawled your site is a guess.

Technical SEO scope is mainly set by a few factors:

• Site size: a 40-page brochure site needs far less checking than a store with thousands of product URLs.
• Platform: some platforms limit what can be changed, which can add workarounds or development time.
• Number of locations: each location page or listing adds templates and content to review.
• Issues found: a handful of redirect and metadata fixes is a different job from a rebuild of site architecture.

Timelines vary mostly because of who ships the fixes. If your developers have a backlog, or changes need approval and testing, a simple fix can wait weeks. Access to your accounts and hosting also affects the start date.

At Pugmarks Media, every engagement begins with a discovery call and a site audit. We then agree a strategy and work plan with you before any changes go live. How long each step takes depends on your site size and how quickly we get access to your accounts.

Cost follows the same scope factors, so we do not publish a single number here. To get a scoped estimate, contact our team or see our SEO services.

Should you handle technical SEO in-house or hire an agency?

In-house works when you have developers with SEO knowledge and time to audit regularly, while an agency suits teams that need specialist diagnosis or lack developer capacity. The right choice depends on your site's size, your team's skills and how often the site changes.

When in-house works: a team with a developer who understands crawling, rendering and indexing can fix issues quickly, because they already control the code and release process. It also helps if someone owns a recurring audit, such as a monthly check of Search Console errors and site speed.

When outside help makes sense: an agency is useful when rankings drop and nobody can find the cause, when a migration or redesign is coming, or when developers are fully booked. Our team of 25+ SEO specialists works on technical fixes alongside SEO services such as content and links.

What to ask before you hire: a good partner should explain exactly how they work and report. Use these questions as a starting point:

• What does the audit cover, and what will I receive at the end?
• Who implements fixes: your developers, theirs, or both?
• Do you agree a work plan with me before changes go live?
• How often will you report, and what will the report show?
• Who owns the code and accounts if we stop working together?

For reference, we start every engagement with a discovery call and a site audit, agree a plan, and report monthly. If you want to discuss your setup, contact our team.