I am thinking about joining the Fediverse.<p>I don't really understand the difference between ActivityPub and Mastodon yet.<p>If I write my own ActivityPub software (server code with web frontend), can I interact with Mastodon users just as if I also were a Mastodon user? Or would I have to implement some Mastodon specific protocols?
Before you go to the trouble of writing your own software, consider using one that's already been written. There are many[0] out there already besides Mastodon.<p>[0]- <a href="https://delightful.club/delightful-fediverse-apps/" rel="nofollow">https://delightful.club/delightful-fediverse-apps/</a>
While everyone is talking about Mastodon because of Twitter, I want people to know that there is <a href="https://pixelfed.social" rel="nofollow">https://pixelfed.social</a> which is alternative to Instagram.<p>Theoretically you should be able to follow anyone from pixelfed on Mastodon and vice versa because both support ActivityPub. I haven't tried doing that myself.
AFAIK: ActivityPub is the protocol used by Mastodon and other platforms (like PeerTube) and so you'd be able to interact with other users using the protocol.<p>If I'm wrong I believe someone will correct me pretty fast but that's my current understanding.
The difference between ActivityPub and Mastodon was already explained by others.<p>If the popular solutions are too complex, maybe you want to take a look at <a href="https://microblog.pub" rel="nofollow">https://microblog.pub</a>, a relatively small and simple AP implementation designed for single-user instances.
For anyone looking to mess around with making a single file ActivityPub server, this looks like a good intro to the spec: <a href="https://socialhub.activitypub.rocks/t/guide-for-new-activitypub-implementers/479" rel="nofollow">https://socialhub.activitypub.rocks/t/guide-for-new-activity...</a><p>That page also links to <a href="https://blog.joinmastodon.org/2018/06/how-to-implement-a-basic-activitypub-server/" rel="nofollow">https://blog.joinmastodon.org/2018/06/how-to-implement-a-bas...</a>, which is a demo of hardcoding one part of the spec from scratch.
Mastodon won't survive this, the Fediverse will. Much as Twitter when it was a Rails app buckled under the load already we see things like <a href="https://github.com/mastodon/mastodon/issues/19505" rel="nofollow">https://github.com/mastodon/mastodon/issues/19505</a> and users of other instances also complain. It's an old crusty complex codebase.<p>So yes you can certainly interact with Mastodon users and you will need to.<p><a href="https://www.r-bloggers.com/2022/10/getting-acquainted-with-mastodon-instances/" rel="nofollow">https://www.r-bloggers.com/2022/10/getting-acquainted-with-m...</a> the largest Mastodon instance has less than a million users. Twitter has, what, 450 million?
no. activitypub is the protocol which all apps in the fediverse use and can talk to each other.
you can create a pixelfed instance account and follow someone on mastodon.social and vice versa. same for interaction between them