What is JavaScript SEO?
Making client-rendered pages discoverable: crawlable links, server or prerendered critical content, unblocked resources, and unique URLs per state. Rendering usually happens, but slow tails hurt time-sensitive pages.
Related terms
Client-Side Rendering
Building page content in the browser with JavaScript after an initially thin HTML shell. Flexible for apps, but critical content and links should still be server-available for crawlers and fast paint.
Server-Side Rendering
Rendering full HTML on the server per request so crawlers and users receive complete content immediately. The SEO-safe default for content pages in frameworks like SvelteKit and Next.js.
Dynamic Rendering
Serving prerendered HTML to bots and client-rendered pages to users. A workaround, not an architecture: useful for legacy apps, but parity drift between the two versions is a constant risk.
Technical SEO
The crawling, indexing, rendering, and performance work that lets search engines reach, understand, and serve your pages. It covers directives, architecture, speed, and structured data rather than words on the page.
Crawling
How search-engine bots discover pages by following links, sitemaps, and directives. If a URL is never crawled, it cannot be indexed no matter how good its content is.
Crawl Budget
The number of pages a search engine will crawl on a site in a given period, driven by server capacity and demand signals. Large or slow sites must spend it on indexable, valuable URLs.