UI automation is necessary for accessibility [LWN.net]

UI automation is necessary for accessibility

Posted Jul 15, 2026 12:14 UTC (Wed) by taladar (subscriber, #68407)
In reply to: UI automation is necessary for accessibility by Cyberax
Parent article: An update on the scraper situation

It is extremely rare that you get the luxury of having the requests a day equally distributed across every second of the day.

PHP on a cloud server likely has a single digit or small double digit number of workers and for something not cached it can easily take a second to generate a page.

Sure, if you only count compiled languages your 250 requests/s might be realistic but the reality is that there are plenty of PHP, NodeJs, Python, Ruby or even Perl based websites that will never reach that and aren't deployed on huge servers because their normal traffic is nowhere near that high.

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UI automation is necessary for accessibility

Posted Jul 15, 2026 16:51 UTC (Wed) by NYKevin (subscriber, #129325) [Link] (2 responses)

> It is extremely rare that you get the luxury of having the requests a day equally distributed across every second of the day.

Just to clarify for folks who haven't done this before: If you graph queries-per-second against time, for the vast majority of web-related services, you get a sinusoid with a period of 1 day, a fairly significant amplitude (relative to the average), and in most cases, the graph looks completely different on the weekend. You must provision for the daily peak and not the average, or else you will fall over. Load balancing, caching, and other middlebox technologies can make the graph a bit flatter (at the origin server), but it will still have a daily peak and you will still need to deal with it.

This is not only true for the origin server, but also for most if not all of its backends (and their backends recursively). You really only get flat QPS from batch jobs running continuously, and even those are often spiky in practice.

UI automation is necessary for accessibility

Posted Jul 15, 2026 16:57 UTC (Wed) by paulj (subscriber, #341) [Link] (1 responses)

> You must provision for the daily peak and not the average,

Well, for January 3rd (boxing day / St. Stephen's day sales) / FA Cup final / $INSERT_APPROPRIATE_ANNUAL_EVENT_HERE.

UI automation is necessary for accessibility

Posted Jul 16, 2026 8:16 UTC (Thu) by taladar (subscriber, #68407) [Link]

With most sites you can probably get away with some flakyness on the busiest day of the year (unless that is specifically what the site is designed to serve of course if it is an event related website) but you certainly won't get away with it on every daily peak.