JavaScript frameworks (such as Next.js, Nuxt.js, SvelteKit, etc.) have long enabled rich client-side interactivity, dynamic UIs, and single-page applications (SPAs).
But the web landscape is evolving rapidly:
- Increasingly, web content is consumed not only by human users via browsers but also by AI systems and crawlers.
- These AI crawlers (including bots from OpenAI, Anthropic, and others) are fetching pages at massive scale. According to Vercel: over 1 billion monthly fetches across its network by AI crawlers combined.
- Critically: many of those crawlers do not execute JavaScript. Vercel found: “none of the major AI crawlers currently render JavaScript.” Vercel
This means that if you build a site or application and rely solely on client-side rendering (CSR) — i.e., the initial HTML returned to the crawler is minimal, and then the JavaScript executes in the browser to build the UI — you risk the content being invisible or inaccessible to those crawlers.
This has always been true for website SEO and one big reason I never really fully dove deep into the javascript ecosystem. Minus all the saturated frameworks, forks and overall unnecessary complexity and third party library dependencies. SEO was too big of a deal to have place holder text aka client side rendering for the raw HTML you get with server side rendering like traditional web frameworks.
Given the rise of AI-driven search, summarization, indexing, and content consumption, this is still a real problem, and a good choice for me to not dive into javascript.
Why SSR Matters (Now More Than Ever)
As javascript frameworks have evolved somewhere along the way they learned or decided maybe they need html output and server side rendering. But not sure most developers have really implemented this to it’s full capabilities or in the case of SEO necessity!
Here are the main reasons why SSR (server-side rendering) should be used heavily (or exclusively) in modern JavaScript frameworks in 2025 and into the future:
1. Crawlers & AI bots often can’t execute JavaScript
As noted above, Vercel’s data show that many AI crawlers fetch HTML, images, etc., but do not execute JavaScript, hence cannot access or interpret content rendered on the client side. Vercel
When essential content (articles, product details, metadata, navigation) is only available after client-side script execution, it may simply be missed or mis?interpreted by the crawler.
Therefore: rendering that content on the server (so the HTML response is complete) ensures visibility.
2. Critical content must be accessible to all “consumers”
Beyond just human users, there are many “consumers” of web content: search engines, AI crawlers, summarization engines, large language models (LLMs) that may sample web data.
By using SSR, you ensure that the initial HTML includes everything you need: meta tags, headings, structured data, main copy, images, links, etc. That means the content is available at fetch time — before any client-side hydration or interactive enhancements.
In Vercel’s recommendation:
“Prioritise server-side rendering for critical content. ChatGPT and Claude don’t execute JavaScript, so any important content should be server-rendered.” Vercel
Thus, SSR improves the reliability of content being discovered, indexed, and used in AI contexts.
3. Improved performance, user experience and SEO
SSR helps by delivering a fully-formed HTML document to the browser, which means: quicker first paint, faster time-to-interactive, and better perceived performance — especially on slower devices or connections.
From an SEO perspective, search engines (traditional ones) prefer content that is accessible without needing heavy client-side execution. While many search engines do some JS rendering, it adds latency and risk. SSR reduces that risk.
In an age where speed, UX, and accessibility matter more (especially given mobile usage), SSR’s performance advantage is relevant.
4. Future-proofing for AI consumption
Given the rapid expansion of AI crawlers and agents, making your content “crawlable” and “understandable” by non-traditional consumers is increasingly important. Vercel’s data show that AI crawler traffic is already a significant percentage of Googlebot’s volume. Vercel
By adopting SSR as a default, you’re reducing dependency on client-side environments (which may change, may not be executed by bots, may be blocked) and instead providing robust content at the source.
In short: you’re designing for a world where bots/agents may fetch your site, interpret it, use its data, repurpose it.
5. More predictable indexing and backlinking
Because SSR gives predictable, static (or semi-static) markup, link structures, meta tags, and content are available immediately. This means better visibility in contexts where indexing or summarizing is done automatically.
In contrast, CSR can lead to inconsistencies: content may not load until after events, may depend on authentication or dynamic calls, may delay or fail altogether for bots.
Practical Implications for JS-Framework Architects & Developers
Here are some actionable takeaways if you’re using a modern JS framework:
- Design your pages so that the initial HTML includes the full content (headings, body text, metadata) — not just skeletons that are filled in by JS later.
- Choose frameworks or modes that support SSR/SSG: e.g., Next.js ’s
getServerSideProps,getStaticProps, or frameworks that support server components. - Avoid relying entirely on CSR for SEO- or AI-critical content. Even if your audience is mainly users, consider the bot/AI consumption angle.
- Monitor crawler behaviour: Observe server logs to see if AI crawler user-agents are fetching and what they’re getting. Are they hitting pages with minimal content? Are there many 404s/redirects? Vercel found high 404 rates from AI crawlers (~34%) meaning inefficient crawling. Vercel
- Manage URLs and sitemaps: As Vercel notes, high 404s and redirect rates hurt crawler efficiency. Ensure clean URL patterns, updated sitemaps, fewer broken links. Vercel
- Prioritise meta & structured data: Because bots often rely on the HTML response without executing JS, ensure your meta tags, OpenGraph, JSON-LD, etc., are included server-side.
- Performance optimisations still matter: Even with SSR, you’ll want caching, CDNs, efficient load of scripts and assets, as the first-load cost and time to interaction still matter for users and bots.
Why “As Much If Not All SSR” May Be the Right Call
Given the above, here’s a summary of why I argue for “as much SSR as possible” in the current era:
- The risk: if you rely heavily on CSR, critical content may be invisible to large segments of crawlers/AI agents.
- The upside: using SSR makes your content reliably accessible, which supports SEO, AI-agent comprehension, linkability, sharing, and performance.
- The cost: SSR can complicate architecture (you might need server infrastructure), increase initial server render cost, may limit some client-only interactivity and dynamic behaviour. But these are often manageable with hybrid or incremental strategies.
- The trend: As AI crawlers grow and become a bigger part of how information is discovered, consumed and reused, designing with SSR puts you ahead of the curve.
Thus: while fully “all SSR” may not always be strictly necessary (depending on your app), it’s prudent to make SSR the default for core content, and treat CSR as the optional enhancement layer.