โš™๏ธ
Technical SEO
Lesson 18 of 22 ยท Crawl Control
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๐Ÿ‡ท๐Ÿ‡บ ะงะธั‚ะฐั‚ัŒ ะฝะฐ ั€ัƒััะบะพะผ

JavaScript SEO & Rendering

โš›๏ธ
React developer
"Our site is a modern SPA built on React. Everything renders client-side. Fast, beautiful, modern!"
๐Ÿค–
Googlebot
"I arrived. Got an empty HTML with <div id='root'></div>. Content loads via JS. I'm adding your page to the rendering queue and will be back in a few days..."
โš ๏ธ The JavaScript SEO problem: Googlebot can render JavaScript, but does so with a delay โ€” through a rendering queue. Content inaccessible before JS executes gets indexed later or incompletely.

Types of Page Rendering

TypeHow it worksSEO
SSR (Server-Side)HTML ready on the serverโœ… Best option
SSG (Static Gen)HTML generated at build timeโœ… Excellent
CSR (Client-Side)HTML built in the browserโš ๏ธ Delay risks
ISR (Incremental)SSG + on-demand updateโœ… Good compromise

What to Check on a JS Site

JavaScript SEO diagnostics:

โ˜ URL Inspection in GSC โ†’ check rendered HTML
โ˜ All nav links use <a href>, not JS handlers
โ˜ Content visible in "View Source" (not just DevTools)
โ˜ No infinite pagination without URL state
โ˜ Meta tags present in the SSR response
โ˜ Using Next.js/Nuxt/Gatsby instead of pure SPA
๐Ÿง‘โ€๐Ÿ’ป
Alex diagnoses an SPA
"Opened URL Inspection in GSC. Rendered HTML was empty โ€” content not indexed. Migrated from CSR to SSR via Next.js. Within a month, 800 pages appeared in the index."
๐ŸŽฏ Recommendation: for new projects, choose SSR or SSG (Next.js, Nuxt, Gatsby, Astro). For existing SPAs โ€” add pre-rendering or a hybrid rendering mode.
๐ŸŽฎ Test yourself: why can JavaScript-heavy sites create SEO problems?
๐ŸŽฏ
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โ† CMS Selection for SEO
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