Glossary /Technical SEO
JavaScript Rendering
The extra step an engine takes to execute a page’s scripts before it can see content that is not in the initial HTML response.
When content is built in the browser rather than sent in the HTML, a crawler has to render the page to see it. Google does this, in a deferred second pass with its own queue and budget. Most other crawlers, and most AI assistants fetching a page, do not — they read what the server returned and nothing more.
The practical consequence is that client-rendered content is visible to a shrinking share of the systems that matter. A page whose headline, body copy and internal links only exist after React runs is fully legible to one crawler and invisible to the rest, which is a poor trade for a marketing site.
The fix is not to abandon a framework. It is to make sure the things an engine needs — title, headings, body copy, internal links, structured data — are present in the server response, and to let scripts enhance from there rather than construct from nothing.