[cbzoiav]

You dropped the API calls bit.

As it stands your site has to go through a TCP handshake then send the request and get the start of the response - at minimum that's 2 round trips. It then gets the JS and CSS tags in the head of the HTML and has to request those - let's assume HTTP/2 so that's another single RT of latency (on HTTP it's at least two depending on if you queue requests or send in parallel).

On 215ms RT latency that is an absolute minimum of 645ms before your JS has even started to be parsed. For a large bundle with a load of vendor code at the top in practice were talking several seconds to getting to the code that makes the API calls to get the content needed to render the first page.

And this is before we talk about any Auth, images, opening a websocket or two and people using microservices as an excuse to require a request for nearly every field on the page... (Or worse multiple requests and applying some logic to them...).

There is a fundamental minimum RT bound to a static JS based web app that is a multiple of a server rendered page. If you cache the HTML and JS bundle it can be worth it but you still need to aggregate data sources for the page on a backend and/or host it in multiple regions.