Mastodawn

"The top-line takeaway is chilling: sites that are explicitly designed as SPAs, and which have intentionally opted in to metrics measurement around soft-navigations are seeing one (1) soft-navigation for every full page load on average."

Amazing research and analysis as always from @slightlyoff https://infrequently.org/2025/11/performance-inequality-gap-2026/

The Performance Inequality Gap, 2026

Embedded in this year's network and device estimates is hopeful news about the trajectory of devices and networks. It has never been easier to deliver pages quickly, but we are not collectively hitting the mark. Indeed, the latest CrUX data shows not even half of origins have passing Core Web Vitals scores for mobile users. Browsers will need to provide stronger incentives. This will be unpopular, but it is clearly necessary.

Alex Russell

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Nolan Lawson Nov 27

@slightlyoff Frankly I'm skeptical of _all_ claims of SPA superiority:

- Paying for slow initial load is amortized across subsequent soft navs
- Soft navs are faster than hard navs
- Any of this is worth breaking the back button

You can always point to one SPA where it works, but in aggregate it doesn't seem to be working.

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Thomas Steiner

Nov 28

@nolan Can you point out one SPA where it actually works well indeed? I'm always so frustrated by GitHub, where even on a WiFi network it's often faster to right-click and open in a new tab.

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Marcus Bointon Nov 28

@nolan @tomayac stack overflow

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Thomas Steiner

Nov 28

@Synchro @nolan Based on some quick testing, Stack Overflow is an MPA. For me, it navigates to a new document for each major view change, like jumping to another question.

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Marcus Bointon

@tomayac @nolan it's true that it's more like a collection of SPAs, but the main question page (I'd guess it's probably >90% of their usage) is an enormously capable SPA in its own right. I've been impressed by its ability to cope with multiple simultaneous editing sessions on the same page, live comment updates, voting, etc, without missing a beat. What's more impressive is it's been doing it for years! It was good while it lasted...