Over on the Fediverse, I said some things :

[on April 27th:]
A bit of me would like to know why the Akkoma Fediverse software is insistently polling the same URL with HEAD then GET requests at five minute intervals for days on end. But I will probably be frustrated if I turn over that rock and applying HTTP blocks to individual offenders is easier.

(I haven't yet blocked Akkoma in general, but that may change.)

[the other day:]
My patience with the Akkoma Fediverse server software ran out so now all attempts by an Akkoma instance to pull things from my techblog will fail (with a HTTP redirect to a static page that explains that Akkoma mis-behaves by repeatedly fetching URLs with HEAD+GET every few minutes). Better luck in some future version, maybe, although I doubt the authors of Akkoma care about this.

(The HEAD and GET requests are literally back to back, with no delay between them that I've ever observed.)

Akkoma is derived from Pleroma and I've unsurprisingly seen Pleroma also do the HEAD then GET thing, but so far I haven't seen any Pleroma server showing up with the kind of speed and frequency that (some) Akkoma servers do.

These repeated HEADs and GETs are for Wandering Thoughts entries that haven't changed. DWiki is carefully written to supply valid HTTP Last-Modified and ETag , and these values are supplied in replies to both HEAD and GET requests. Despite all of this, Akkoma is not doing conditional GETs and is not using the information from the HEAD to avoid doing a GET if neither header has changed its value from the last time. Since Akkoma is apparently completely ignoring the result of its HEAD request, it might as well not make the HEAD request in the first place.

If you're going to repeatedly poll a URL, especially every five or ten minutes, and you want me to accept your software, you must do conditional GETs. I won't like you and may still arrange to give you HTTP 429s for polling so fast, but I most likely won't block you outright. Polling every five or ten minutes without conditional GET is completely unacceptable, at least to me (other people probably don't notice or care).

My best guess as to why Akkoma is polling the URL at all is that it's for "link previews". If you link to something in a Fediverse post, various Fediverse software will do the common social media thing of trying to embed some information about the target of the URL into the post as it presents it to local people; for plain links with no special handling, this will often show the page title. As far as the (rapid) polling goes, I can only guess that Akkoma has decided that it is extremely extra special and it must update its link preview information very rapidly should the linked URL do something like change the page title. However, other Fediverse server implementations manage to do link previews without repeatedly polling me (much less the HEAD then immediately a GET thing).

(On the global scale of things this amount of traffic is small beans, but it's my DWiki and I get to be irritated with bad behavior if I want to, even if it's small scale bad behavior.)