JavaScript SEO Explained - How Google Crawls Modern Websites

If your website’s built on something like React, Vue, or Angular, you’re probably publishing content with JavaScript. It can look great for users - but it can be a bit of a nightmare for SEO if you’re not careful.

The problem is that Google doesn’t see your site the same way your visitors do. A user might get the full page instantly, including images, text, buttons, the lot. But Google’s crawler? It sees a blank page first, and only later tries to render all that JavaScript. This delay between the two means that sometimes it doesn’t even bother.

If your site relies too heavily on JavaScript to display key content, Google might miss the important stuff entirely. And no content means no rankings.

Common JavaScript SEO Problems

Let’s break down where things go wrong.

If your content only appears after the JavaScript runs, things like blog posts, product listings, or even key navigation menus, then there’s a real chance Google never sees it. That "view more" button or slick infinite scroll might be great for users… but if it relies solely on JavaScript with no fallback? Google might not find the extra content hiding behind it.

Then there’s hydration issues (yes, that’s a real term). Basically, what the server sends doesn’t match what the browser ends up displaying after JavaScript loads. That mismatch confuses Google, and you end up with broken or missing content in the index.

And if you’re running a single-page app where URLs change but the page doesn’t technically reload? That can totally break Google’s ability to understand what your site’s actually about.

Solutions for JavaScript-Heavy Sites

Let’s say you need JavaScript. What can you do? You don’t need to worry - there are ways to make it SEO-friendly.

First up, there’s server-side rendering (known as SSR) or static site generation (SSG). These are the gold standard. They make sure Google gets clean, fully rendered HTML right away, without any waiting around. Or you can use progressive enhancement. That just means your core content and links work even if JavaScript doesn’t load.