What should the file-extension for ActivityPub / ActivityStreams documents be?

I.e., for application/activity+json data?

I've been using .activity

Ex: filename.activity

(The extension cannot be .json or .jsonld if you want to be able to detect it just based on the file-extension.)

What do you think?

#ActivityPub #ActivityStreams #FediDev

Did you know our Threat Intel channel publishes to #ActivityPub? We're serious about the "Federated" in "Independent Federated Intelligence Network!" This is the firehose of all posts in our "Threat Intel" category.

@threatintel

In *theory* you should be able to follow this test user:

@你好@i18n.viii.fi

But I can't find any Fediverse software which actually supports non-ASCII usernames.

If you are able to see the user, its description, and its avatar - please send me a screenshot 🙂

#Fediverse #ActivityPub #Unicode

RE: https://social.wake.st/@liaizon/116476200944284702

It would be really cool if #Friendster ended up being federated and built on top of #activitypub !

wakest likes your bugs ⁂ [they/them] » 🌐 2026-04-27
@liaizon@social.wake.st

RE: https://tacobelllabs.net/@ultranurd/116475019811050460

someone bought https://friendster.com and is trying to make a new social network on it, though the idea that the domain alone was worth $30k is so silly to me.

After another exciting 6th week of Fedibook, a somewhat brief weekly update is ready.

Thank you to everyone who has provided feedback and involved me in the interesting world of ActivityPub protocol challenges.

https://about.fedibook.net/fedibook-week-6/

#fedibook #thefedibookProject #activityPub

Can an ActivityPub 'Place' also be an Actor?

https://www.w3.org/TR/activitystreams-vocabulary/#dfn-place

With followers, an outbox, etc.

That could be useful for both real-life places, and fictional places in stories, and in video games.

#ActivityPub #ActivityStreams #FediDev #FediFiction #FediGames

What makes an ActivityPub Actor an Actor?

I think it is probably a bad idea to just restrict it to things with 'type': "Application", "Group", "Organization", "Person", and "Service". Restricting it to just those would mean you couldn't have new actor types (and sub-types) in the future.

So then, do we do it in a duck-typing way? And if "yes", how?

Maybe if something has an "inbox" OR and "outbox" it is an Actor. I.e., it could have just one of those.

#ActivityPub #ActivityStreams #FediDev

Should an ActivityPub 'Place' be used to represent a fictional place?

https://www.w3.org/TR/activitystreams-vocabulary/#dfn-place

Such as a fictional place in a story, or a video game?

#ActivityPub #ActivityStreams #FediDev #FediFiction #FediGames

Recently I subscribed to the Monsterdon group @monsterdon , & I've started adding it to certain posts (e.g. Monsterdon poll options info). Hoping that it might improve reach as this account is on a "minor" instance, because I'm still not 100% clear how Fediverse federation or groups work.

Today I discovered tags.pub when it boosted one of my posts for the KungFuSat watch party. Apparently a bot that boosts posts with certain hashtags. I think like a Mastodon group... but without a specific human as admin?

https://tags.pub/

I've followed several watch party-related tags.pub accounts (not all watch parties have a related tags.pub account yet) on this alt account to see what effect it might have, e.g. will it improve how many watch party posts I see here and when they arrive (because up to now, too many posts missing or late when I try using it for a watch party).

#Mastodon #Fediverse #ActivityPub #MastodonGroups #TagsPub

Alt...

List of recent follows on this Mastodon account of mine, showing multiple watch-party-related tags.pub accounts & the Monsterdon fedigroups account. MonsterMiru HustleTV SundayFunnies FridayThrillerClub Monsterdon KungFuSat

#HolosSocial is a project that lets users run their own #ActivityPub server on a device (Android/iOS). Would a desktop version interest you? For purists, dynamic DNS could replace the relay entirely, which is simply not realistic on mobile.
Main account: @HolosSocial
Your opinion?

full account migration could leverage a trusted third party service that simply serves authorization attestation (also for in the event the origin becomes unavailable), allowing remote servers to simply rewrite data/relations without having to delete and refetch.

ap devs: let's chat about this, I'm already building this for Loops and Pixelfed

#fullAccountMigration #ActivityPub

Week in Fediverse 2026-04-24

Servers

- Hollo v0.7.11
- Lemmy v0.19.18
- Wafrn 2026.04.02
- Ibis v0.3.2
- Ktistec v3.3.6
- ActivityPub for WordPress v8.1.0
- Gush v0.0.36
- Iceshrimp.NET v2026.1-beta
- Mitra v5.2.0
- tootik v0.22.0
- NeoDB v0.14.0
- Vernissage Server v1.34.0
- PieFed v1.6.19
- ActivityPub Bots v1.1.1

Clients

- Jerboa v0.0.86
- Holos v1.4.0

Protocol

- FEP-35b7: Fediverse Servers, Instances, and Tenants
- FEP-ae49: Semantic Routing for ActivityPub

Articles

- Copyright and DMCA Best Practices for Fediverse Operators

-----

#WeekInFediverse #Fediverse #ActivityPub

Previous edition: https://mitra.social/objects/019d9ce7-bae8-7d4c-da66-27acb019a9e6

Top 4 ActivityPub fediverse platforms by number of active instances:

• mastodon (10462, source: @mastodon)
• misskey (2393, source: @misskey)
• peertube (2096, source: @peertube)

I don't know how much WordPress instances with ActivityPub plugin installed so we can call it a fediverse instance. But I think it's not a huge number comparing with total WordPress instances. So don't complain why doesn't WordPress is on the list.

#fediverse #mastodon #misskey #peertube #activitypub

No one is saying you should always be using the latest bleeding-edge software.

But if you can’t keep your community updated at least twice (2x) a year — when people are depending on you — you really shouldn’t be running a Fedi site.

#Mastodon #Misskey #PixelFed #PeerTube #FediAdmin #Fediverse #ActivityPub

Is there a #fediverse enabled #blog (or something like that) which supports long posts which are regularly extended and treats them like growing threads?

I want to write my daily stories in a way that they can be followed/found from e.g. mastodon, but also be read in one page.

Or maybe I could just teach #silverbullet to publish both the whole page and the latest paragraph to separate systems.

#activitypub #software

Kleines Fediverse-Gedankenexperiment für den Abend 🌙

Stell dir vor, dein E-Mail-Anbieter würde dir verbieten, Mails an Gmail-Nutzer zu schicken, weil die auf einem "anderen Server" sind.

Klingt absurd? Genau das machen Twitter/X, Instagram & Co. täglich mit euren sozialen Kontakten.

ActivityPub sagt: Nö, Interoperabilität ist kein Feature, sondern Standard. 📡

#Fediverse #ActivityPub #Dezentralisierung #Mastodon

Before anybody thinks we're trying to arrange for a battle of the protocols, #activitypub vs #atproto ... that's not the intention.

Instead, for people not deep down in the technical specs, these talks should give you an idea how these protocols work and you can better understand why their designers made different design choices and tradeoffs.

And for people who know one protocol well but not the other, we'd like to create ...

Evan Prodromou, editor of the ActivityPub standard, will give a talk at FediForum on Tuesday, April 28, titled:

"How To Bullshit Your Way Through a Conversation about ActivityPub"

Have you ever wondered how #ActivityPub actually works? Come join us to find out, online! https://fediforum.org

/cc @evanprodromou

Here is something neat:

I maintain a #WordPress blog, and use the #ActivityPub plugin to connect to the #Fediverse .

And it seems that recently this plugin added the option of an extended footer to blog entries. This footer includes both a Fediverse "follow" button and a list of Fediverse Followers.

I think this is very useful because it makes the Fediverse more visible in the world at large - few people out there know what the Fediverse actually is, but many read blogs.

If you use Wordpress, I recommend that you check this plugin out, and use it for your site. You can see the effect here:

https://sunkencastles.com/2026/04/20/1101/

Alt...

A footer for a blog entry, showing first a "follow on the Fediverse" element, and then a list of Fediverse Followers.

@serigala_tropis not simple. Because it's not just about move your posts on old instance, but their posts already published and recorded by other instances.

Some tools exist to import old posts (specific to platform type), but other servers will still link those posts to the old place.

As additional note, post's identifier in #activitypub is their url. So it wouldn't be simple to change that.

You can migrate one profile to a new account, but it will just move your following and follower list, not posts.

there is now also an english version https://changinggraph.org/en/index.html

#changinggraph #rdf #activitypub #c2s #fediverse

Many people are talking about decentralized social media protocols like #ActivityPub and #ATProto and all the amazing things one can do with them. But do you actually know how they work?

We thought we'd do something about this. Come to #FediForum next week if you are curious and like to find out!

Registration: https://fediforum.org

The fediverse, ATProto/Bluesky and Nostr are not competitors.

The real competitors (Meta, X, YouTube) probably love to see such division in us.

Let's remember who we're really up against, and stop trying to compete with other open platforms and protocols.

Use that energy to convince people to leave the real competitors and join us.

Thanks to @anewsocial, we have a universal bridge to the future of a open social web.

A bridge to the future 🚀

#ActivityPub #ATProto #Nostr

Week in Fediverse 2026-04-17

Servers

- Mastodon v4.5.9
- Stegodon v1.8.4
- NodeBB v4.10.3
- Lemmy Development Update March 2026
- Fedle: A daily word game played on the Fediverse

Clients

- Fedilab v3.38.0
- Blorp v1.12.4

Tools and Plugins

- Altbot v2.6
- bookwyrm.koplugin: A read-only BookWyrm plugin for KOReader
- threadcat: Converts a Mastodon thread to Markdown

For developers

- funfedidev schemas v0.1.1
- Mastodon.py v2.2.0

Protocol

- FEP-7b29: Federated Signup Requests

Articles

- FR#159 – Sovereign Tech Agency funds Mastodon

-----

#WeekInFediverse #Fediverse #ActivityPub

Previous edition: https://mitra.social/objects/019d78bb-737a-54cf-14a1-973c0a00393a

Hashtag following also allow URLs to RSS feeds of ActivityPub objects (like e.g. https://mastodon.social/tags/ThankYouTuesday).

Users can now configure a webhook to receive an HTTP POST for every notification. This can be useful for implementing bots that react to activities, like autorepliers, chatbots or interactive textual games (see snac(1) for more information).

The number of pending follow confirmations is shown next to the "people" link.

Faster performance metrics (contributed by dandelions).

Improved lowercasing in hashtags (contributed by postscriptum).

A search-by-url tweak for implementations that return 200 for invalid webfinger queries (e.g. piefed).

Mastodon API: added follow confirmation endpoints, fixed collisions in attachment file names.

Fixed potential crashes in attachment uploads.

https://comam.es/what-is-snac

If you find #snac useful, please consider buying grunfink a coffee or contributing via LiberaPay.

#snacAnnounces #FrugalFediverse

Notifications are now shown in a more compact way (i.e. all reactions are shown just above your post, instead of repeating the post ad nauseam for every reaction).

New command-line option unmute to, well, no-longer-mute an actor.

The private timeline now includes an approximate mark between new posts and "already seen" ones.

Fixed a spurious 404 error in the instance root URL for some configurations.

https://comam.es/what-is-snac

If you find #snac useful, please consider contributing via LiberaPay: https://liberapay.com/grunfink/

#snacAnnounces

This release has been inspired by the song The Answers to the Questions by #Christabell and #DavidLynch.