You cant really cache the dynamic content produced by the forges like Gitlab and, say, web forums like phpbb. So it means every request gets through the slow path. Media/JS is of course cached on the edge, so it's not an issue.

Even when the amount of AI requests isnt that high - generally it's in hundreds per second tops for our services combined - that's still a load that causes issues for legitimate users/developers. We've seen it grow from somewhat reasonable to pretty much being 99% of responses we serve.

Can it be solved by throwing more hardware at the problem? Sure. But it's not sustainable, and the reasonable approach in our case is to filter off the parasitic traffic.

You've gotten several comprehensive responses so far and I want to add a niche corner that people might assume might not have the bot problem but still does.

I run a website that hosts tools for my family: games and a TV interface for the kids, remote access to our family cloud and cameras, etc. Sensitive things require log in and have additional parameters required for access of course.

I specifically blocked bots from search engines so my site is never indexed, as I'm not selling anything nor want any attention, as well as some other public non-malicious bots in case they communicate with Google, just to be safe there, and my robots.txt doesn't allow anything.

I assume then, that the only way a bot could even find my site is to do what the indexers do: brute force try every single possible ipv4 address hoping to hear something back, as my domain should not be known (and isn't simple enough to be quickly guessed), and most traffic must be malicious, or indexing (AI overview and other scrapers won't be finding it via web search).

Since it isn't indexing, and keeping everything in simple black and white boxes, my remaining traffic is family or malicious bots, and 99.9% isn't family.

I currently have the most strict bot-blocking setup I could come up with, which nicely cut down on quite a bit of traffic, but I do still receive ~2k attempts per day, which as you can imagine, still is around 99% not traffic, as I have fewer than 20 kids, and my kids aren't using the site nonstop.

Conveniently, my setup has never accidentally blocked a family member, so I'm pleased with the setup.

I think there's a few things at play here

- AI scrapers will pull a bunch of docs from many sites in parallel (so instead of a human request where someone picks a single Google result, it hits a bunch of sites)

- AI will crawl the site looking for the correct answer which may hit a handful of pages

- AI sends requests in quick succession (big bursts instead of small trickle over longer time)

- Personal assistants may crawl the site repeatedly scraping everything (we saw a fair bit of this at work, they announced themselves with user agents)

- At work (b2b SaaS webapp) we also found that the personal assistant variety tended to hammer really computationally expensive data export and reporting endpoints generally without filters. While our app technically supported it, it was very inorganic traffic

That said, I don't think the solution is blanket blocks. Really it's exposing sites are poorly optimized for emerging technology.

They are a scourge, they never rate-limit themselves, there are a hundred of them, and a significant number don’t respect robots.txt. Many of them also end up our meta:no-index,no-follow search pages leading to cost overruns on our Algolia usage. We spend way too much time adjusting WAF and other bot-controls than we should have.

Yes, it's that BIG of a load: https://status.sr.ht/issues/2025-03-17-git.sr.ht-llms/