Plans to adjust streaming SSR behavior for Googlebot UA after React 19.2?

[bendvc]

Hi maintainers 👋

After upgrading to React / ReactDOM 19.2.x, we noticed a change in streaming SSR behavior for Googlebot user agents and wanted to ask if there are any plans or recommendations around this.

Observed change

• React 19.1.x: With a Googlebot UA, onAllReady often produced HTML with resolved Suspense content already inlined.
• React 19.2.x: Initial HTML now includes Suspense fallbacks, with resolved data delivered via streamed Flight chunks, even for bots.

This seems related to the React 19.2 change where Suspense boundary reveals are batched before first paint.

Impact

• SEO (Perceived): No practical impact — But we are working on a large framework used by large ecom vendors and typically they want to know that SEO crawlers will see the HTML in it's full state. This is more about giving our customers confidence and now having to say "trust the process, the crawler will execute the javascript"

Question

Are there any plans or recommended patterns for treating bot UAs differently (e.g. opting bots into synchronous / fully inlined rendering) while keeping streaming enabled for human users? Or is per-route bot detection and inlining the intended approach going forward?

Thanks!

[nicreaskdjasd]

React19.2 enabled the progressiveChunkSize feature for SSR.You can opt-out by setting it to Infinity

https://react.dev/reference/react-dom/server/renderToPipeableStream#rendertopipeablestream

[bendvc]

Thanks @nicreaskdjasd

I'm wondering if anyone from the team wants to comment on weather this option is something that is going to be used in the server entry by default. Our starter store template (our customers copy) currently doesn't expose the server entry and ideally I'd like to avoid exposing that extra additional mental overhead.

[sergiodxa]

The React docs recommend the current approach instead of using progressiveChunkSize

But if this works actually better, I recommend you to send a PR to the templates repo so every new RR app will have that configured.

[bendvc]

@sergiodxa I think this is what the default server entry does already, albeit in a little more clever way, here.

This logic, and what react recommends did work in 19.1, but no longer does in 19.2. I suspect that the change would be in this project and not the templates.