Technical SEO explained.

Crawling - when Google cannot find your site

Before Google can rank your pages, it has to find them. Crawl problems are caused by robots.txt errors, broken internal links, excessive click depth or missing XML sitemaps. Search Console shows crawl errors in the Coverage report.

Understanding crawl budget

Google does not crawl endlessly. On large sites (>10,000 URLs) you need to control what gets crawled. That includes excluding unimportant filter URLs via parameter handling, paginating cleanly and avoiding soft 404s.

Indexing - getting the right page into the index

Crawling alone is not enough. Google decides which pages are indexed. Canonical tags steer the right variant into the index. For language versions you need hreflang tags. For non-indexable content (filter pages, internal tools), use noindex.

Rendering - JavaScript issues

Modern SPAs (single page applications) only render content once JavaScript has run. Google does render JS, but only partially and with a delay. If your content appears late, Google misses it. Server-side rendering (SSR), static site generation (SSG) or hybrid approaches solve this.

Performance - Core Web Vitals as a ranking signal

Since 2021, Core Web Vitals have been confirmed ranking factors. Three metrics: LCP (Largest Contentful Paint, <2.5s), INP (Interaction to Next Paint, <200ms), CLS (Cumulative Layout Shift, <0.1). Mobile counts for more than desktop. PageSpeed Insights and CrUX data show the real-world values. Improving these gives you a direct lever to improve your Google ranking.

Schema markup - structured data

Schema.org markup helps Google understand your content. It also enables rich snippets in the SERPs (star ratings, FAQ accordions, breadcrumbs). Essentials: Organization, Breadcrumb, Article, Product. Optional depending on the use case: FAQ, HowTo, AggregateRating, LocalBusiness. The same clean structure also helps language models attribute content correctly; what that looks like in practice is described on the page Structuring content for language models (LLMO).

Checklist: technical search engine optimisation

Technical SEO is the part of search engine optimisation that determines whether a search engine can process your website at all. Before we talk about content or backlinks, we check the technical foundations. The following checklist summarises the points we go through in every SEO audit. You can use it as a rough set of questions for your own site, but it is no substitute for a full crawl report.

• Crawling and indexing: Can a web crawler such as Googlebot reach and index the relevant pages? The robots.txt file (Robots Exclusion Standard) controls what may be crawled, but says nothing about indexing. That is the job of noindex and the canonical tag.
• Google Search Console: The Index Coverage Report shows which URLs actually end up in the index and which have been excluded by the search engine. We use Google Search Console as our primary source because it reflects Google LLC’s own perspective.
• Loading time and page speed: Long loading times cost rankings and conversions. We measure page speed with real field data and prioritise optimising the Core Web Vitals over attractive lab scores.
• Duplicate content: Several URLs with the same content dilute signals. A correctly set canonical tag helps here by telling the search engine which version is preferred.
• Redirects: 301 redirects must run cleanly and without chains, otherwise link equity is lost. This is especially critical during a relaunch.
• SSL certificate: HTTPS is mandatory; a valid SSL certificate is now standard.
• Structured data: By using structured data (Schema.org), you make content machine-readable for search engines and increase the likelihood of rich snippets appearing in search results.

Relaunch: why technical SEO matters most here

In a relaunch, URL structures, templates and the CMS often change all at once. Without a sound technical plan, pages are no longer crawled correctly or drop out of the index. We plan the necessary 301 redirects in advance, check every important URL and, after go-live, verify in Google Search Console that Google can index the new pages correctly. That way the visibility built up over years is preserved instead of disappearing with the old system.

To be honest, technical SEO measures do not solve ranking issues that are actually down to the content itself. They are the prerequisite for ensuring that good content and a fast-loading site reach the search engine and the user in the first place. If the technical aspects are in order but the content is thin, we’ll say so openly. We do not sell technical reports that, in practice, do nothing to change your position in the search results.

For us, technical SEO is part of our ongoing support as an SEO agency in Heidelberg: the audit lays the foundation, and content and link building build on it.