I'm unconvinced.

  Basic page renders were taking 200-400ms.

I've never seen this. Next.js is very fast for basic pages.

  If a Google crawler or our Ahrefs SEO monitoring tool hit multiple pages at once, the site would start crashing multiple times per week.

This just seems like code issue and not Next.js. Plenty of sites use Next.js and have billions of views/year.

  Large pages, especially ones with dynamic content, could spike well beyond 700ms.

This might have something to do with the database/server being far away and nothing to do with Next.js.

  We built our own server-side rendering system using plain React and Express.

Could explain the above inefficiency. Usually when you build your own server, it sits as close to your DB as possible.

  We already knew how to build SSR—it’s not hard.

It's actually really hard to do SSR with React at scale and good client side. One thing Next.js (and other modern frameworks) do very well is that the initial load is SSR, but subsequent loads are client-side.

Truthfully, they should have picked an SSG generator. It's better than using SSR, and certainly better than using a custom SSR solution. It's a marketing site with little to no database content.

  import { Component } from "mui";

  import { Component } from "mui/path/to/component";

The lack of any substance to their claims besides vague hand waving is a tell tale sign that they don’t have solid engineers working on this project. If they had specific GitHub issues documenting this behavior or code samples then it would be much more plausible. I’m sure there are some issues but the performance improvements they’re getting are far too large to be anything besides their own fault.

Additionally being able to replace their implementation in 3 days is a sign of extremely shoddy engineering. If you can replace it in 3 days but you can’t fix it then you’ve had irresponsible maintainers.

I’d recommend Docusaurus for a static docsite over NextJS. It’s got a lot of batteries included.

NextJS is a framework. You can make it extremely slow. No framework can save you from yourself.

Lol I'm not going to take advice from an agency that pops up a email dialog that gives debug error message on empty entry, plus I can't dismiss the popup to read the rest of the article.

I'd like to know why they ditched NextJS, but if they're so bad at webpages I can't read the article on my device (iphone SE 3) that I can't dismiss the popup, I don't know that they're worth listening to.

Sticking to my SSR sites with Go, Fiber, and Go Templates plus a touch of HTMX for interactive islands. Fast AF, simple, reliable. Great dev and user experiences.

  The same company that built its entire identity around Jamstack and static site generation pivoted to serverless, then became the cheerleaders of SSR—the complete opposite of what they originally pushed.

This is wrong. Next.js was originally created to make SSR easy for React.[0] There was no easy way to do it back then. Almost all React apps were client side rendered and had terrible initial load speeds.

The SSG/Jamstack came later as features.

They didn't pivot from SSG to serverless. These aren't even comparable things. Serverless is just lambda functions. SSG is generating static files from React.

Vercel (formerly Zeit) pivoted from always-on servers to serverless functions. Next.js SSR can function in serverless or always-on server mode.

[0]https://web.archive.org/web/20170511054633/https://zeit.co/o...

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Hilarious

Just use php. SSR since 1999