Interesting, do instgram and facebook etc allow third party clients?

No, but unlike Twitter their advertiser tools are at least halfway decent.

One of the tools used is Buffer [0], and they seem to support both Instagram and Facebook, and it seems that they are going to continue with Twitter as well.

[0]: https://buffer.com

Note: They seem to support "Instagram, TikTok, Facebook, Twitter, Pinterest, LinkedIn, and Google Business Profile"

Buffer's support for non-business Instagram is "set a reminder for you to post by hand" because Instagram removed scheduled posting ability a good long while back. I suspect their non-business Facebook support is similar.

I know I was a heavy user until (uh) 5? years ago when Instagram and Facebook posting was nerfed into uselessness.

Buffer's not a third-party client (in the sense of Tweetbot etc.), though.

You can't consume or publish to a personal Facebook profile or an individual Instagram account; it's restricted to Facebook Business Pages, Groups, and Instagram Business accounts.

It does compete with the Meta Business Suite, though.

Those aren't the same APIs that were turned off for third party clients though, correct?

Who knows? Probably someone who got fired, that is.

Disabling APIs won't win you any friends

My understanding is they didn't turn off the APIs, they disabled API keys for any large clients

Which 3rd party apps specifically were used by marketers and are now banned?

Having worked with many PR/Marketing/Media brand teams I do not know of one group that utilized twitter client in any of their workflows -- they all used a mix of third party clients for reading and other integrations/clients for posting and managing conversations and ad work. Sure much of the API surface area for latter still works but there was a goodly portion of impacted folks on these clients that were the same people that were on the same teams that impact ad spend and brand usage.

I've never seen a PR/Marketing tweet from any of the bespoke artisanal apps (tweetbot, twitterific etc) Hootsuite, buffer are web apps, not for "ride or die" iOS nerds

One of the big ones Buffer [0] do not believe that they will be impacted this may not be an issue [1]

[0]: https://buffer.com

[1]: https://twitter.com/buffer/status/1616418191718207488

It would appear that Elon understands his paying customer's after all. Cynical interpretation would be that he just made Twitter API access more scarce and therefore valuable.

Still, mine is just a guess.

edit: Come to think of it, didn't FB eventually moved from super open API to.. friend and family model?

IIRC, FB was originally public-first before (lawsuits). Not API, just default privacy settings.