As Google continues to fine-tune its algorithms in 2025, web developers and SEO professionals alike are under increasing pressure to deliver fast, accessible, and well-structured websites. If your site isn’t ticking the right boxes from a performance and technical website health perspective, chances are you’re already falling behind.
So, let’s break down the most pressing developer-side SEO priorities for 2025: what’s changed, what still matters, and what new practices are shaping the future of search visibility. Whether you’re building from scratch or optimising an existing site, these are the areas where your dev and SEO teams need to align.
Core Web Vitals: INP Takes Centre Stage
Let’s start with the big one — Core Web Vitals. Google’s performance metrics have been an essential part of technical SEO since their introduction, but in 2025, the spotlight is firmly on INP (Interaction to Next Paint).
What is INP?
INP measures the time it takes for a page to respond visually to user input. Unlike its predecessor, FID (First Input Delay), which only captured the first interaction, INP tracks the slowest interaction across a page’s lifecycle — giving a more realistic picture of how users actually experience your site.
Why it matters:
A sluggish INP score often indicates bloated JavaScript, poor main thread management, or layout shifts causing jank. Optimising for INP isn’t just good for rankings — it’s good for users. Prioritise:
• Reducing long tasks and JavaScript execution time
• Using web workers to offload processing
• Keeping DOM size manageable
• Avoiding layout thrashing
A solid INP score (ideally under 200ms) is now one of the clearest signs of ideal website health and high performance.
Crawlability and Indexability: Don’t Get Ignored
You can build the fastest, prettiest site in the world — but if search engines can’t crawl and index it properly, it may as well be invisible.
Clean URLs
Avoid messy URL parameters and dynamic strings. Stick to clean, descriptive URLs that follow a consistent structure. Use hyphens instead of underscores and keep URLs short and meaningful.
Canonical Tags
These are vital for avoiding duplicate content issues. Whether you’re using filters, pagination, or different versions of a product page, make sure your canonical tags point to the preferred version.
Robots.txt
A misconfigured robots.txt can block search engines from important resources like scripts or images. Use it intentionally — not reactively — and test changes in Google Search Console before deploying.
XML Sitemaps
A well-maintained sitemap is a roadmap for search engines. Include only indexable URLs and make sure it’s updated automatically whenever new content is added or removed.
Technical SEO in 2025 is as much about discoverability as it is about speed. If bots can’t see your content, neither can your customers.
JavaScript SEO: SSR, Hydration, and Rendering Realities
Modern websites are heavily reliant on JavaScript, but search engines still struggle with fully rendering client-side apps. If your critical content or navigation relies on JavaScript, you need to make sure it’s being rendered in a way search engines can understand.
Server-Side Rendering (SSR)
SSR delivers a fully rendered HTML page to the browser, improving crawlability and perceived performance. It’s a go-to for content-heavy sites and platforms like Next.js, Nuxt, and Astro make implementation easier than ever.
Hydration
With partial hydration or islands architecture, you can load static HTML quickly, then hydrate only the interactive bits using JavaScript. This approach balances speed and interactivity, which is crucial for both INP and indexability.
Pre-rendering
If SSR isn’t an option, pre-rendering key pages using tools like Rendertron or Prerender.io can still help ensure that bots see your content. Just make sure pre-rendered versions stay in sync with dynamic updates.
The goal? Deliver something meaningful — fast — to both users and bots.
Site Structure: Hierarchy, Links, and Mobile-First Thinking
Your site’s structure directly affects both crawl efficiency and user navigation. In 2025, mobile-first indexing is no longer the future — it’s the present. Everything about your structure needs to reflect that.
Logical Hierarchy
Pages should be arranged in a clear and logical way. Use a flat structure where possible, with important pages no more than three clicks from the homepage. Group related content together and create thematic clusters.
Internal Linking
Don’t rely solely on menus. Use contextual internal links to connect related pages. This not only spreads link equity but also helps crawlers understand how your content fits together. Tools like Screaming Frog or Sitebulb can visualise internal linking opportunities.
Mobile Usability
Google still uses mobile-first indexing, which means your site needs to be fully functional and navigable on smaller screens. Avoid hidden content, ensure clickable elements aren’t too close together, and test with real devices — not just emulators.
A strong site structure isn’t just about crawlability — it improves UX, time on site, and ultimately conversions.
Schema Markup: Speak Google’s Language
Schema.org markup adds context to your content, helping search engines understand what your pages are about — and in many cases, making you eligible for rich snippets in the SERPs.
Key Markups to Use in 2025:
• WebPage: A foundational schema type that helps define the page type and purpose.
• BreadcrumbList: Improves site hierarchy and navigation clarity in search results.
• Product: Essential for eCommerce sites to display pricing, availability, and reviews.
• LocalBusiness: Must-have for location-based businesses targeting local SEO visibility.
• FAQ, How-To, and Article: Still powerful for getting rich features in SERPs.
Use tools like Google’s Rich Results Test or Schema.org validator to confirm implementation. JSON-LD remains the preferred format in 2025 — easier to maintain and less prone to conflict.
Proper structured data won’t directly impact rankings, but it does improve click-through rates and indexability, which are just as important for SEO and website health.
Avoiding Bloat: Lighten the Load
One of the biggest enemies of performance — and by extension, of Core Web Vitals — is code bloat. Every line of unnecessary JavaScript or CSS is costing you points, both in load speed and user satisfaction.
Here’s how to trim the fat:
• Minify JS/CSS/HTML: Remove whitespace, comments, and unnecessary characters
• Compress Images: Use modern formats like WebP or AVIF and serve scaled images
• Lazy Load Everything: Defer offscreen images, videos, and non-critical resources
• Code Split: Load only the JavaScript needed for each page
• Remove Unused Code: Audit with tools like Lighthouse or Chrome DevTools Coverage tab
• Limit Third-Party Scripts: Ads, trackers, and widgets can kill performance
Every byte counts. Lighter pages mean better INP scores, faster load times, and more satisfied users.
Conclusion: 2025 Demands Smarter, Leaner, More Accessible Sites
In 2025, technical SEO isn’t just an afterthought or a one-off audit — it’s baked into the development process from day one. From how you structure your HTML and serve JavaScript, to how fast your pages respond to input and how bots discover content, every technical decision impacts how your site performs in search.
By focusing on the right dev-side SEO priorities — Core Web Vitals (especially INP), clean architecture, indexability, smart rendering strategies, and eliminating bloat — you’re not just chasing rankings. You’re building a healthier, faster, and more resilient website for users and search engines alike.
It’s not about doing everything — it’s about doing the right things well.
