Current aspects, best practices, and Tools
Why Technical SEO Remains Crucial: an Overview.
What’s technical SEO?
Technical SEO forms the foundation for online visibility and must not be neglected in 2025. Even with AI and machine learning influencing search environments, a clean technical foundation remains essential for search engines to efficiently crawl, index, and understand websites. Content and backlinks alone are insufficient—only when crawlers can smoothly access the website structure and users enjoy a fast, secure experience can other SEO measures fully take effect. Simply put: without a technical foundation, even the best content remains invisible.
Optimizing Crawling and Indexing
A central goal of technical SEO is to optimally utilize crawl budget and indexing. Google crawls only a limited number of URLs per website within a certain time—this crawl budget should not be wasted on unnecessary or irrelevant pages. Recommended practices include:
Removing unnecessary pages or excluding them from crawling:
Filter and search result pages, outdated pages, and test environments cause crawl waste and should be excluded via robots.txt or noindex. Analyzing server or crawl logs helps identify such pages.
Clean website structure:
A common myth is that a "flat" site architecture is always better. Instead, content should be logically structured in categories or directories. Clear hierarchical URLs (e.g., /products/jackets/men) and meaningful category pages guide both crawlers and users. Important content should be reachable within a few clicks via internal links (general rule: a maximum of 3 clicks) to ensure crawlers overlook nothing essential.
Optimizing redirects:
Avoid lengthy redirect chains and unnecessary redirects. Each redirect costs crawl budget and can increase loading times. Old or broken URLs should directly point to the target URL via 301 redirect. Regularly review the website's redirect logic and minimize intermediate steps.
Managing duplicate content:
Use canonical tags (canonical) to ensure that when content is accessible via multiple URLs, only the primary URL is indexed. This prevents confusion in the index. Likewise, implement hreflang tags for multilingual sites so each language/country version is correctly recognized by Google.
Additional important tools for indexing control are XML sitemaps and Google Search Console. An up-to-date sitemap lists all indexable pages—this file should be submitted via the Search Console to inform Google of new or changed content. In the Search Console itself, webmasters can check indexing status, identify crawling errors, and inspect individual URLs with the URL Inspection tool. This allows quick identification of whether important pages are successfully crawled and indexed or if robots.txt rules, noindex tags, or other technical issues prevent indexing.
Page Load Speed and Core Web Vitals
Page speed is a critical ranking factor and significantly contributes to user experience. Slow websites frustrate users (high bounce rates) and are rated poorly by search engines. Modern technical SEO therefore places considerable emphasis on optimizing loading times and Core Web Vitals:
Image Optimization:
Large, uncompressed images are major causes of slow load times. Images should be compressed before upload or converted into efficient formats like WebP.
Utilize Browser Caching:
Caching allows returning visitors to load static resources (JS/CSS files, images) from their local cache. Appropriate configuration (e.g., via .htaccess or CMS plugins) significantly reduces load times.
Minimize Render-Blocking Resources:
JavaScript and CSS files that block rendering should be minimized, combined, or loaded with delay (keywords defer or async). Many CMS offer options or plugins for this purpose.
High-Performance Hosting:
The web host impacts server response times. Adequate server resources and possibly a CDN are essential for fast delivery. Particularly with shared hosting, ensure guaranteed performance.
Core Web Vitals measure specific aspects of load performance and interactivity. Google primarily evaluates: Largest Contentful Paint (LCP) for main content load time, Interaction to Next Paint (INP) (since 2024, replacing FID) for responsiveness during the first user interaction, and Cumulative Layout Shift (CLS) for visual stability. These metrics should be in the optimal range. Google Search Console's Core Web Vitals report highlights URLs requiring optimization. Typically, recommended measures align with general page speed optimizations—for instance, solving LCP issues via image and server optimization or addressing CLS issues through fixed dimensions for images/elements.
Mobile Optimization as Standard
Since Google has fully transitioned to mobile-first indexing, the mobile version of a website is the primary basis for indexing and rankings. Excellent mobile presentation is thus mandatory:
Responsive Design:
Layout must automatically adapt to various screen sizes. Modern websites and CMS themes are typically responsive by default, but it's worth checking for display errors.
Mobile Usability:
Navigation and buttons should be easily operable on touch devices (sufficient size and spacing). Text should be easily readable on small screens.
Testing:
Google's free Mobile-Friendly Test tool quickly assesses if Google considers the page mobile-friendly, also providing suggestions for improvements.
Mobile Page Speed:
Mobile users often have slower connections, making performance issues even more impactful. Previously mentioned speed optimizations are particularly crucial for mobile.
Poor mobile implementation (e.g., hidden content, non-loading elements, or difficult operation) directly harms both user experience and mobile index rankings. Thus, technical SEO must equally monitor mobile and desktop, prioritizing a seamless mobile experience.
Security and Website Accessibility
HTTPS encryption is now standard and is considered a ranking signal by search engines. Every website should have a valid SSL certificate and consistently serve all requests via HTTPS. The transition is typically straightforward with Let's Encrypt and hosting tools; afterward, automatic redirects from HTTP to HTTPS must be established, and internal links updated. Browsers mark unsecured pages as unsafe—this is unacceptable for user trust and SEO.
Proper handling of redirects and status codes is also part of technical hygiene: When URLs change (e.g., after a relaunch), 301 redirects are mandatory to transfer old rankings and links to new URLs. Missing or incorrect redirects lead to 404 errors, sending users and crawlers into dead ends. Regular SEO audits should therefore check and resolve broken links and HTTP status codes. Google Search Console helps identify Not Found pages.
Structured Data for Improved Understandability
Structured data (schema markups) help search engines semantically categorize page content. Markups like JSON-LD define precisely what a page contains—whether it's a product with price and ratings, an article with author and date, a local business with address, FAQs, events, and more. The benefits are twofold: firstly, search engines process information more efficiently and accurately. Secondly, certain markups enable rich results (enhanced snippet displays like star ratings, FAQ dropdowns, recipe images, etc.), increasing visibility in search results.
Google’s John Mueller emphasizes that structured data remains crucial even in the age of AI search results—providing clearly formatted facts that bots can easily interpret. Webmasters should focus on schema types actively used in search results (an updated overview lists common markups and their SERP impact).
Implementation is possible without programming, thanks to numerous generator tools and CMS plugins (such as Yoast, RankMath, Schema Pro for WordPress). After implementation, verify correct recognition with Google's Rich Results Test. For local businesses, the LocalBusiness markup is particularly beneficial, highlighting addresses, opening hours, and additional details on Google.
Considering JavaScript and Rendering
Modern websites frequently use JavaScript for interactive content—however, from an SEO perspective, caution is required concerning critical content loaded exclusively on the client side. Googlebot can render JavaScript now, but with delays and additional effort. Many AI-based crawlers (LLMs), however, currently cannot execute JS. Therefore, the following best practices are recommended:
Render Important Content Server-Side:
All key content (texts, product details, navigation, internal links) should be present in the initial HTML code. Content appearing only via JS could be overlooked by crawlers. If a web app relies heavily on client-side rendering, Dynamic Rendering or a hybrid solution (serving a pre-rendered version for crawlers) can help.
Avoid Hidden Links and Navigation:
Menu links or connections visible only via clicking JS elements are problematic. Internal links should ideally be embedded in HTML, as neither Google nor LLM crawlers reliably detect JS-dependent navigation. An example is accordion or tab content—ensure important sections are not permanently collapsed.
Polyfill for Missing Rendering Capability of AI Bots:
As ChatGPT-User, PerplexityBot & co. currently can't execute JS, webmasters must find solutions for bots to still "see" content. Two pragmatic solutions from practice are: (a) creating separate landing pages specifically for AI crawlers, providing all essential info purely in HTML (possibly on a dedicated subdomain). These pages can be specifically allowed for AI bots via robots.txt without prominently featuring them in the regular index. (b) Enhance Structured Data specifically: Interestingly, some AI crawlers in tests could read JSON data and similarly embedded content. Providing the most important content additionally as structured data (e.g., FAQ, HowTo) in the source code ensures LLMs can extract this information.
For debugging rendering issues, the Chrome extension View Rendered Source is useful to compare original HTML vs. rendered DOM, identifying content loaded exclusively via JavaScript. If unsure, follow "Progressive Enhancement"—deliver basic content statically first, then add extra features via JS. This ensures accessibility for users and all crawlers alike.
Managing Crawlers with robots.txt
The robots.txt file remains a vital instrument for guiding crawlers. Here are some current recommendations:
- Allow Important Bots, Block Unnecessary Ones:
By default, robots.txt should permit all major search engine bots (User-agent: *) to crawl all public areas while excluding unimportant or sensitive sections (admin panels, login pages, shopping carts, etc.). This focuses crawling efforts on relevant content. - Specifically Handle AI Crawlers:
In 2025, new bots from AI services are emerging. OpenAI and Microsoft, for example, utilize their own crawlers (OAI-SearchBot, ChatGPT-User, Bing Chat via PerplexityBot, etc.), and Google has introduced the Google-Extended agent for AI functions. It's advisable to update the robots.txt file to include rules for these bots. A proven practice is allowing crawling for AI search bots while excluding AI training bots. Specifically: allow bots like OAI-SearchBot, ChatGPT-User, or PerplexityBot with Allow: /, while disallowing bots like GPTBot (OpenAI’s training bot), CCBot (Common Crawl), and Google-Extended via Disallow: /. This approach lets AI systems access current site information without content being integrated into long-term training data. - Caution with Google-Extended:
Google uses this user-agent to improve generative AI features (e.g., SGE). Blocking Google-Extended via robots.txt prevents your content from being used in AI responses but risks exclusion from AI Overviews. Decide carefully whether visibility in Google’s AI results is desired—in doubt, consider removing this entry to avoid losing visibility. - Avoid Unintentional Blockades:
Regularly audit the robots.txt to ensure no bots or directories are inadvertently blocked. Some webmasters mistakenly used rules like User-agent: OpenAI-GPT or Google-Extended: Disallow /, unintentionally preventing all AI bot access. Regular checks avoid unintended content invisibility.
The idea of a specialized llm.txt file for AI crawlers is also discussed, but according to Google, there’s currently no evidence that AI search systems use such a file. Thus, prioritize proven methods (robots.txt, meta tags).
(Tip: Use tools like TechnicalSEO's Robots Tester to validate your robots.txt file—many AI user-agents are already listed, allowing preemptive rule checks.)
Technical SEO Aspects for AI Search (LLM Optimization)
The growing prevalence of Large Language Models and AI search assistants (ChatGPT, Bing Chat, Perplexity, Google SGE, etc.) has introduced new dimensions to technical SEO. Although the traffic share from these AI tools is currently low (often significantly less than 1% of total traffic), it is steadily increasing. Forward-looking strategies thus include the following considerations:
Indexability Equals Visibility in AI:
Non-indexed content appears neither in classic SERPs nor in AI Overviews. LLM-based systems like Google's AI Overviews draw from existing search indices. Hence, traditional crawling and indexing optimizations (mentioned above) remain fundamental prerequisites for appearing in AI responses. Google Bard or Gemini, for instance, cite only content crawled and understood by Googlebot. Therefore, technical SEO is also the foundation for AI optimization.
Server-Side Content for AI Crawlers:
Since AI crawlers cannot (yet) render JavaScript, relevant content must be directly present in HTML for these bots. (This topic was already covered under JavaScript and Rendering.) Explicitly avoid JS-only content—several experts explicitly emphasize this.
Use Structured Data and Clear Formats:
LLMs prefer structured, well-defined information, bringing traditional SEO tactics like FAQ sections or clear tables and lists back into focus. Frequently asked questions with concise answers on the website benefit not only PAA snippets but also help AI systems extract content. Additionally, structured data (as previously discussed) aids machine systems in efficiently capturing content. Google recommends JSON-LD, as it's easiest for AI crawlers to parse.
Content Coverage Over Keyword Focus:
For AI-generated answers, topical authority matters most. Rather than targeting individual keywords, it's advisable to comprehensively cover a topic (Topical Authority). Extensive, well-structured guides or clusters of interlinked posts signal comprehensive knowledge to models. Initial analyses show LLMs prefer detailed, clearly structured content—quality and depth outperform superficial texts.
Digital PR and Mentions:
Backlinks remain crucial, but mentions of brands in trusted sources particularly count for AI responses. AI systems frequently refer to third-party sources for complex queries. If an AI Overview asks about the "best online marketing agency," answers often derive from articles or lists mentioning those agencies—not necessarily from their websites. Strengthening online reputation and presence in industry media, forums (e.g., helpful responses in Q&A communities), and directories increases the likelihood of your brand appearing in AI results. Digital PR is becoming increasingly important.
Monitoring and Measuring AI Traffic:
Tracking AI-driven traffic currently remains challenging. Tools like Google Analytics identify visits from ChatGPT, Bing Chat, or Perplexity as referrals, e.g., bing.com/chat or chat.openai.com appear in referrer data. In GA4, using segments and regex filters allows isolation of such referrals, showing which pages AI visitors access. (For example, a regex on ^(copilot\.microsoft\.com|perplexity\.ai|chatgpt\.com)/referral$ aggregates these accesses.) Additionally, SEO tools offer new functions: Since late 2024, Semrush provides AI Overview tracking, and SERanking launched an AI Overview Tracker in 2025. Specialized services like Trackerly.ai, Peec.ai, BrandMonitor for LLM, etc., also analyze how often a brand is mentioned in AI results. This is an emerging monitoring field—initially, manual checks (e.g., directly querying ChatGPT about "[your brand]") provide valuable insights into AI visibility.
Ultimately, LLM SEO best practices don't differ drastically from traditional SEO. Rather, they build upon it: a strong technical foundation, high-quality content, and trust signals (authority) remain key. AI optimization thus isn't a radical departure from known SEO principles, but rather a conscious extension and prioritization tailored to new search environments.
Useful Tools and Practical Tips
The implementation of technical SEO is facilitated by numerous tools. Here is a selection of recommended aids and best practices:
Google Search Console (GSC):
Essential and free. GSC provides insights into indexing status, crawling issues, Core Web Vitals analysis, mobile-friendly tests, and detected structured data. Regular use of GSC enables early detection of technical errors—e.g., pages dropped from the index, crawler errors (DNS, server errors, blockages), or pages with poor user metrics.
PageSpeed Tools:
Google PageSpeed Insights and GTmetrix analyze loading speeds and provide concrete optimization suggestions. Lighthouse (in Chrome) or WebPageTest.org are also useful for identifying performance bottlenecks. These tools can reveal scripts that cause long render times or excessively large images.
Mobile Testing:
Besides GSC’s Mobile Usability Report, the standalone Mobile-Friendly Test quickly verifies mobile display quality. Test each critical page, especially after major design or template changes.
Crawlers and Audits:
Desktop crawlers like Screaming Frog SEO Spider (free up to 500 URLs) simulate website crawling, uncovering technical SEO issues—e.g., 404 error pages, lengthy redirect chains, missing or duplicate titles/meta descriptions, and oversized pages. These tools enable rapid technical site audits. Pro tip: Screaming Frog can be integrated via API with ChatGPT for automated content improvement suggestions per crawled page.
Other Helpful Tools:
- XML-Sitemaps.com Generator (if the CMS lacks a sitemap)
- TechnicalSEO.com Robots Tester (validate robots.txt rules, including AI bots)
- Browser extensions like View Rendered Source (JS check) or SEO Minion (displays hreflang tags, broken links, etc.)
- Logfile Analyzer (optional for larger sites to precisely track Googlebot's crawl path)
Checklists & Processes:
It's advisable to work with an SEO checklist or a defined audit process covering all areas. A possible DIY review routine could be:
- Review GSC data (indexing report, Core Web Vitals, mobile, enhancements);
- Scan website with crawler and collect issues (404s, redirects, duplicate content, missing tags);
- Measure loading speeds of key pages;
- Conduct mobile tests;
- Verify HTTPS and SSL certificate (no mixed-content warnings);
- Check sitemap and robots.txt;
- Test structured data;
- Document and prioritize findings.
Such a step-by-step approach ensures nothing critical is overlooked and identifies the most important tasks. Prioritization is crucial—address critical errors first (e.g., indexing blockages, significant speed issues), then optimize "nice-to-haves."
Finally, a practical note: Technical SEO is not a one-off project but an ongoing process. Changes in website code, new features, content, or Google updates can necessitate technical adjustments at any time. Combining automated monitoring (GSC alerts, regular crawls) with manual reviews maintains website technical health.
Technical SEO in 2025 builds on proven basics like speed and structure, while adapting to AI-driven changes.
Modern Technical SEO in 2025 demands established fundamentals—fast loading times, clean structure, and error-free implementation—and simultaneously requires attention to emerging developments like integrating AI-powered search functionalities. The good news: Those already following proven SEO practices don't need to completely reinvent their approach. Instead, it's about consistently applying these best practices and extending them at specific points. A clear website structure and accessibility form the foundation for all SEO channels. Building upon this, high-quality content and targeted optimization ensure visibility both in organic rankings and AI-generated results. Therefore, despite changes driven by AI, technical SEO remains the indispensable cornerstone of a successful search strategy.