Technical SEO Checklist: Website Optimisations for 2025.
Article — We walk you through the essential technical SEO optimisations you need to implement to make sure your site performs well in 2025. These steps are designed to help you boost site speed, improve user experience, and enhance your rankings, all without getting bogged down by complicated jargon.
Posted by Marina Cheveleva
07.07.2025
In 2025 technical SEO has become an even more critical part of ensuring your website ranks well in search results. With Google's evolving algorithms, the increasing importance of AI-driven search experiences, and the ongoing need for a fast, mobile-optimised site, technical SEO has to be on your radar.
In this article, we’ll walk you through the essential technical SEO optimisations you need to implement to make sure your site performs well in 2025. These steps are designed to help you boost site speed, improve user experience, and enhance your rankings, all without getting bogged down by complicated jargon.
Let’s break it down:
In this guide, we outline an effective SEO technical checklist for performance
1. Core Web Vitals
What Are Core Web Vitals and Why Do They Matter?
In 2025, Core Web Vitals continue to be a key ranking factor. These metrics - LCP (Largest Contentful Paint), FID (First Input Delay), and CLS (Cumulative Layout Shift) - measure how well your website performs from a user’s perspective. Here’s why they matter:
- LCP measures how fast the largest content element (like an image or block of text) on the page loads.
- FID measures how quickly the website responds when a user interacts with it (clicks a button, fills a form, etc.).
- CLS tracks how much the content moves around as it loads, which can negatively affect user experience.
How to Improve Core Web Vitals
- Improve Server Response Time: A slow server is one of the biggest culprits behind a poor LCP score. Opt for a reliable hosting provider that offers fast server response times. If your server is slow, consider upgrading your hosting plan or using a content delivery network (CDN).
- Optimise Images: Large images can significantly slow down page loading. Tools like TinyPNG or ImageOptim can compress your images without sacrificing quality. Try using the newer WEBP image format, which offers better compression for smaller file sizes.
- Reduce Render-blocking Resources: Make sure that JavaScript or CSS files are not blocking the page from loading. Use free tools like Google’s PageSpeed Insights to identify these bottlenecks and implement strategies like deferred loading or inline critical CSS.
- Avoid Layout Shifts: Large layout shifts during page load can cause a poor CLS score. Ensure that images, ads, and fonts have fixed sizes to avoid shifting as the page loads.
For more detailed tips on improving Core Web Vitals, check out our Core Web Vitals Impact on SEO post.
2. Mobile-First Optimisation
Mobile-First Indexing: What Does It Mean for Your Site?
As of 2025, Google uses mobile-first indexing, meaning it evaluates and ranks websites based on their mobile version, not their desktop version. With over half of internet users browsing via mobile, it's crucial that your website is optimised for mobile devices to rank well.
If your site’s content is not accessible at all with a mobile device, it will no longer be indexable.
How to Optimise for Mobile
- Responsive Design: Ensure your site automatically adapts to fit any screen size, from smartphones to tablets to desktops. Responsive design ensures your site provides the best experience, regardless of device.
- Improve Mobile Speed: Mobile users often have slower connections, so optimise images and eliminate unnecessary resources that slow down page load times. Use tools like Google’s Mobile-Friendly Test to check if your pages are mobile optimised.
- Mobile-Friendly Navigation: Avoid small fonts or hard-to-tap buttons. Make sure your mobile site has simple navigation, large touch-friendly buttons, and clear calls to action.
3. AI & Structured Data
How AI Impacts SEO in 2025
With the introduction of AI (such as Google’s SGE), search results are becoming increasingly personalised. AI-driven search rankings focus more on search intent and user experience than just relevant keyword matching.
Why Structured Data Matters
Structured data (also called schema markup) allows search engines to better understand your content and display it in rich snippets, such as product reviews, FAQs, and knowledge panels. This helps your site stand out and improves click-through rates (CTR).
How to Use Structured Data
- Add Schema Markup: Use JSON-LD format to mark up key content, such as articles, products, and reviews.
- Improve Visibility in Search: Adding structured data helps your content appear in rich snippets and featured snippets, giving you an edge in search results.
- Test and Validate Your Schema: After adding structured data, it’s essential to test and ensure it’s correctly implemented. Use these free tools to validate your schema and check for any errors:
- Schema Markup Validator: This tool helps you validate your schema markup to ensure there are no errors.
- Google’s Rich Results Test: Use this to test how Google displays your structured data in rich results and ensure it’s correctly interpreted.
For a detailed guide on using schema markup, check out our Schema Markup Strategies.
4. SEO Audits
How to Conduct a Comprehensive SEO Audit in 2025
Regular technical SEO audits help you identify areas that need improvement. These audits ensure your website remains crawlable, indexable, and optimised for performance. Here's what to focus on:
- Crawl Errors: Use Google Search Console to identify pages that Google can’t crawl. Fix these issues to ensure all your pages are indexed.
- Site Speed: Page speed continues to be a top-ranking factor. Use Google’s PageSpeed Insights to test and improve your site’s load time.
- Duplicate Content: Use Siteliner to check for duplicate content and resolve issues using canonical tags or 301 redirects.
- Broken Links: Regularly check for broken internal and external links using tools like Ahrefs and Screaming Frog.
A thorough SEO audit ensures your website is optimised for search engines. In addition to using Google Search Console, consider using Bing Webmaster Tools to monitor how your site performs on Bing, identify crawl errors, and optimise your content for Bing’s search algorithms.
5. JavaScript SEO
Making JavaScript Sites Crawlable
JavaScript-heavy websites can be challenging for search engines to crawl and index. However, Google is improving its ability to crawl JavaScript-rendered content. If your site relies heavily on JavaScript, here’s how to improve crawlability:
- Prerendering: Pre-render your JavaScript content to create static HTML versions for search engines to crawl.
- Server-Side Rendering (SSR): Implement SSR to send fully rendered content to Googlebot, ensuring your content is crawled and indexed quickly.
Tools like Screaming Frog can help detect JavaScript crawling issues, while Google Search Console allows you to fetch and render JavaScript.
6. Internal Linking & Site Architecture
Why Internal Linking is Critical
Internal linking helps distribute page authority and makes it easier for search engines to crawl your site. A well-organised site structure improves both user experience and SEO.
- Organise Your Content: Create a clear structure where key pages are easily accessible via internal links.
- Audit Your Internal Links: Regularly audit your internal linking to ensure all links are working and lead to relevant content.
For more on improving your site’s structure, check out our Site Architecture for SEO guide.
7. HTTPS & Security
Why HTTPS is Essential for SEO
Since HTTPS is a ranking factor, moving to a secure connection not only helps protect your users but also boosts your SEO.
- Get an SSL Certificate: Ensure your website is secure by using SSL certificates to enable HTTPS.
- Secure Your Data: HTTPS ensures all data exchanged between your website and users is encrypted, making it safer for transactions and information sharing.
Sitemaps are the second Discovery option most relevant for Googlebot.
- Create an XML Sitemap: Ensure your website has a properly structured XML sitemap that includes all the important pages on your site. This helps Googlebot and other search engine crawlers find your content quickly and efficiently.
- Keep Your Sitemap Updated: Regularly update your sitemap as you add or remove pages from your site. Google Search Console and Bing Webmaster Tools allow you to submit and monitor your sitemap’s status.
- Avoid Overloading Your Sitemap: Your sitemap should not exceed 50,000 URLs or 50MB in size. If you have a large site, consider splitting your sitemap into multiple files or using a sitemap index file.
9. Robots.txt
The robots.txt file is used to tell search engines which pages they are allowed or disallowed to crawl. This file helps you manage and control search engine bots to prevent them from indexing unnecessary pages, such as admin pages, duplicate content, or low-value pages.
- Set Up Your Robots.txt File: Make sure your robots.txt file is correctly configured to allow or block specific pages or directories. You can block certain areas of your site that don’t need to be indexed by search engines.
- Test Your Robots.txt File: Use the robots.txt Tester in Google Search Console to check if the file is correctly blocking or allowing search engine crawlers to access the intended pages.
- Avoid Blocking Important Pages: Be careful not to accidentally block important pages or resources, such as your CSS or JavaScript files, that are needed for proper rendering and indexing.
For more information on setting up your robots.txt file, refer to our guide on SEO Website Structure.
10. Site Migrations
Best Practices for Site Migrations
When migrating your website to a new domain or platform, it’s crucial to follow the right steps to avoid losing SEO value.
- Set Up 301 Redirects: Make sure all old URLs properly redirect to the new ones.
- Update Internal Links: After migration, ensure all internal links are updated to avoid broken links.
For further guidance on site migrations, take a look at our SEO Migration page.
11. Continuous Monitoring
Why Ongoing Monitoring is Crucial
Technical SEO is not a one-time task. Regularly monitor your site’s performance to ensure everything runs smoothly.
- Track Metrics: Use Google Analytics and Google Search Console accounts to track important technical SEO metrics like crawl errors, page speed, and mobile usability.
- Conduct Regular Audits: Continuously audit your site to fix any issues before they affect your rankings.
Always look at your own data. Understand how users are reaching your website and how they behave. Act before you see changes in the Google Search Console. By then, it’s often too late.
Tools Recap for Effective Technical SEO
As you implement the steps in this 2025 Technical SEO Checklist, here are the essential tools you can use to test, validate, and optimise your website's performance:
- Google’s PageSpeed Insights: To test your website speed and Core Web Vitals like LCP, FID, and CLS.
- Google Search Console: Monitor your site’s performance, track crawl errors, and submit sitemaps and robots.txt files.
- Google Analytics: Track and analyse your site’s traffic and performance metrics, especially for mobile-first optimisation and site speed.
- Screaming Frog: Identify broken links, duplicate content, and crawl errors.
- SEMrush: Conduct in-depth SEO audits, track rankings, and perform keyword research.
- Ahrefs: Check for backlinks, broken links, and duplicate content.
- Bing Webmaster Tools: Monitor your site’s performance on Bing, check for crawl errors, and submit sitemaps.
- Schema Markup Validator: Test and validate your structured data (schema markup).
- Google’s Rich Results Test: Test how Google interprets your structured data and displays it in rich snippets.
- Robots.txt Tester (Google Search Console): Test your robots.txt file to see which pages are blocked or allowed for Googlebot and other search engine bots.
Technical SEO Checklist Recap
In 2025, staying ahead with technical SEO is key to keeping your website optimised for both search engines and users. Here’s a quick recap of the essential technical SEO elements you need to implement:
- Core Web Vitals: Focus on LCP, FID, and CLS to ensure a fast, responsive, and stable user experience.
- Mobile Optimisation: Make your site mobile-friendly with responsive design and optimise for mobile users and page speed.
- AI & Structured Data: Implement structured data (schema markup) to help search engines better understand your content and improve visibility in rich snippets.
- Technical SEO Audit: Regularly audit your website for crawl errors, duplicate content, broken links, and site speed to ensure it remains healthy and search engine-friendly.
- JavaScript SEO: Optimise JavaScript-heavy sites with techniques like prerendering or server-side rendering (SSR) to ensure proper crawlability and indexing.
- Internal Linking & Site Architecture: Build a logical site and url structure and ensure effective internal links to distribute page authority.
- HTTPS Security: Ensure your site is secure with SSL certificates and HTTPS, which also boosts your SEO success.
- Sitemap: Keep your XML sitemap updated and submit it to Google Search Console for better crawl efficiency.
- Robots.txt: Use the robots.txt file to control which pages are crawled and indexed by search engine bots, ensuring efficient use of your crawl budget.
- Site Migrations: Handle 301 redirects and update internal links properly during site migrations to avoid SEO losses.
- Continuous Monitoring: Use Google Analytics, Google Search Console, and regular site audits to track and improve your site's performance over time.
By following this comprehensive technical SEO checklist, you can ensure your website is fully optimised for 2025 and years to come. For expert assistance and personalised guidance, feel free to reach out to our team. We’re here to help your website stay ahead of the curve.
