Fetching – Crawlers request pages via HTTP and parse initial HTML response
Evaluation – DOM is updated based on JS execution and assets are downloaded
Rendering – Page is rendered like a browser to index fully updated DOM
Processing – Rendered HTML is parsed again for links, metadata, and indexing
Limited ability to execute code (no infinite loops)
May lack full support for newer APIs and libraries
Restricted crawling budgets to reduce server load
Can‘t scroll or interact with pages like a user
1. Slow Server Response and Page Render Times
According to Chrome User Experience data, the average Time to First Byte (TTFB) is 600-900ms, while typical Time to Interactive (TTI) can range from 2200ms to 8800ms:[Insert graph highlighting TTFB and TTI distributions]
Pages with poor Lighthouse Performance scores and metrics like Largest Contentful Paint (LCP) over 2.5 seconds may underperform in rankings.
<head> block rendering and delay First Contentful Paint.
async on external scripts stops them from blocking DOM construction. Using techniques like code splitting and tree shaking reduces bundle sizes for faster loading.
Solutions involve proper server-side redirects, canonical tags, and Sitemap guidance on the definitive URL for a given page.
4. Inconsistent Metadata and Structured Data
Crawlers read metadata like page titles, descriptions, and schema markup from raw HTML source code. But client-side frameworks can overwrite these dynamically on page render.
5. Dynamically Loaded Content Hidden from Indexing
Solutions involve server-side rendering (SSR), static site generation (SSG), or using snapshot services like Prerender.io.
Defer non-critical scripts using
defer attributes so they only run after initial HTML parsing. But defer interactivity dependent scripts.
2. Use Code Splitting and Route-Based Chunking
With webpack and Parcel, you can split bundles into routes or components that load dynamically on demand. This lazy loads code as users navigate through your SPA.
Code splitting minimizes initial scripts required for first paint and chunks logic based on what‘s required by each view.
3. Adopt Server-Side Rendering for SEO
Server-side rendering (SSR) pre-renders HTML on the server instead of client-side. This ensures optimized, SEO-friendly pages are delivered to crawlers.
Frameworks like Next.js make it easy to add SSR to React apps. Traditional server-side languages like PHP also work well.
4. Preload Critical Assets and Lazily Load the Rest
<link rel="preload"> directive lets you load crucial scripts, styles and fonts ahead of time without blocking. Lazy load remaining assets only when needed.
This guarantees critical resources are fetched early while improving TTI and LCP.
5. Follow Core Web Vitals Best Practices
Target an LCP under 2.5s, FID under 100ms, and minimal CLS regression to align with Google‘s ranking evaluation.
6. Use React Helmet for Server Rendered Metadata
The React Helmet library lets you inject SEO-friendly metadata from React components on both client and server side.
This prevents crawler issues from client-only frameworks overwriting initial page titles and descriptions.
7. Implement Prerendering for AJAX Content
8. Follow Structured Data Best Practices
Keep your schema cleanly formatted within HTML tags. Use validation tools to catch issues.
Case Study 1: Housing.com
Indian real estate portal Housing.com rebuilt their website with Angular Universal server-side rendering.
This improved their page load times by 50% and organic traffic by 100% within 6 months. Their bounce rate also dropped from 60% to 40%.
Housing.com CTO Vivek Jain commented:
"Angular Universal resolved our SEO bottlenecks and helped us accelerate rendering performance. These improvements translated directly into user satisfaction and conversion metrics."
Case Study 2: Kittyhawk
Enterprise drone operations platform Kittyhawk migrated from a traditional Rails application to a React-based single page app.
Search engine visibility increased rapidly after properly optimizing their React architecture for SEO.
Case Study 3: Foodsense
By tuning webpack builds and optimizing code splitting, they cut initial bundle sizes from 1MB to 100KB. First paint improved from 6s to under 2s while search traffic rose steadily.
Key Takeaways and Next Steps
The key conclusions from this comprehensive guide are:
References and Sources