Technical SEO does not make content rank. It makes content eligible to rank. Every item below is something that, when broken, stops otherwise good pages from performing — and most of them are invisible in a browser, which is why they survive for years unnoticed.
Key Takeaways
- If a page's content only appears after JavaScript runs, treat it as at risk.
- One canonical URL per piece of content — trailing slashes and parameters quietly split ranking signals.
- Internal links are the strongest lever most sites never pull.
Crawlability and indexing
Start by confirming search engines can reach and are allowed to index your pages. A single stray disallow rule or a leftover noindex from a staging deploy can remove a section of the site from search entirely.
Check the rendered HTML rather than the source you wrote. What matters is what a crawler receives.
- robots.txt allows the pages you want indexed
- No stray noindex tags left from staging
- XML sitemap lists live, canonical, indexable URLs only
- Important content is present in server-rendered HTML
One URL per piece of content
Duplicate URLs split ranking signals between copies of the same page. The usual culprits are trailing slash variants, http and https, www and non-www, and query parameters from campaigns and filters.
Pick one canonical form, redirect the rest with 301s, and declare it with a canonical tag on every page.
- 301 redirect http to https and pick one of www or non-www
- Self-referencing canonical tags on every indexable page
- Consistent trailing-slash handling
- Parameter handling for filters, sorting and tracking
Structure and internal linking
Internal links tell search engines which pages matter and how they relate. A page reachable only from the sitemap is a page you have told nobody to care about.
Keep important pages within three clicks of the homepage, use descriptive anchor text instead of 'click here', and make sure the navigation is real links in the HTML rather than JavaScript-driven menus that mount only on interaction.
- Important pages within three clicks of the homepage
- Descriptive anchor text
- Navigation links present in server-rendered HTML
- Breadcrumbs, marked up with structured data
Metadata, structured data and speed
Every indexable page needs a unique title and meta description, one h1, and a heading hierarchy that reflects the content rather than the styling. Structured data should describe what is actually on the page.
Then Core Web Vitals: LCP under 2.5 seconds, INP under 200 milliseconds, CLS under 0.1, measured against real users rather than a lab test on your machine.
- Unique titles and descriptions, no duplicates across the site
- One h1 per page, headings in a logical order
- Structured data that matches visible content
- Core Web Vitals passing on field data
Frequently asked questions
What is technical SEO?
Technical SEO is the work that lets search engines crawl, render, understand and index a site: robots and sitemap configuration, canonical URLs, server-rendered content, site structure, internal linking, structured data and page performance. It makes content eligible to rank rather than making it rank.
How often should I run a technical SEO audit?
Quarterly for most sites, and after any redesign, replatform or major release. Technical problems are usually introduced by deployments rather than appearing gradually, so auditing after change is more valuable than auditing on a fixed calendar.
Does JavaScript hurt SEO?
JavaScript itself is fine; depending on it to render primary content is the risk. Google can execute JavaScript but does so in a second pass that may be delayed, and other crawlers often do not. Serve important content in the initial HTML through server rendering or static generation.
What is the most common technical SEO mistake?
Duplicate URLs serving the same content — trailing slash variants, http and https, www and non-www, and parameter versions — which split ranking signals between copies. The fix is one canonical form, 301 redirects for everything else, and self-referencing canonical tags.