JS SEO Lab — Homepage (RSC + Streaming)

Renderability mapping across rendering modes, page types, and image patterns.

Featured

Mode-level rendering differences
How SSR, SSG, ISR, RSC, CSR, and Edge differ in what bots actually receive.
Image rendering patterns
Vanilla <img>, next/image, JS-injected lazy loading — three patterns tested per page type.
Bot pathway split
Batch crawlers vs on-demand fetch tools, tracked separately.

Recent observations

This page is part of an open methodology experiment. Bot hits are logged to a public-ish tracker (anonymized IPs, hashed); marker UUIDs let us aggregate visibility per cell.

Deferred section (RSC streaming test)

This block is rendered by an async server component that awaits a 200 ms timeout before returning. Under RSC streaming, the response is split into chunks: the page shell + first synchronous content ships immediately, this section is appended to the stream when the promise resolves.

Marker B (deferred chunk): rsc-stream-chunk-2

If a bot logs marker_in_ssr=true for the page-level marker AND can see this deferred marker, the bot reads the whole stream.
If only the page-level marker is visible, the bot terminates the connection after the first chunk.

Loading deferred section…