ActivityPub Protocol

ActivityPub Protocol

ActivityPub is an open, decentralized social networking protocol that allows users to share content and interact with each other across the internet. It is based on the concept of the Activity Stream, which is a standard format for representing activities or events that happen on a social networking site.

One of the key features of ActivityPub is that it allows users to interact with each other in a decentralized manner. This means that users do not need to rely on a central server or platform to communicate with each other. Instead, they can communicate directly with each other using the ActivityPub protocol.


This decentralized approach has several benefits. For one, it makes it much harder for a single entity to censor or control the content that is shared on the network. It also makes the network more resilient to outages or other disruptions, as there is no single point of failure.

ActivityPub is also designed to be interoperable, meaning that it can be used by different social networking platforms and applications. This allows users to interact with each other regardless of the platform or application they are using.

One of the most popular platforms that uses ActivityPub is Mastodon, a decentralized, open-source social networking platform. Mastodon allows users to create their own "instances" or sub-networks within the larger Mastodon network. This allows users to have more control over the content that is shared on their instance, as well as the users who can participate.

In addition to Mastodon, there are many other platforms and applications that use ActivityPub, including PeerTube, a decentralized video sharing platform, and, a decentralized blogging platform.

Overall, ActivityPub is a powerful tool for building decentralized, open, and interoperable social networking platforms and applications. It gives users more control over their online interactions and helps to create a more open and equitable internet.

ActivityPub with .NET

Currently, things are not looking so good as far as the number and quality of NuGet packages for .NET with support for ActivityPub is concerned. At the moment there is only a single NuGet package listed in NuGet: ActivityStreams . But it looks like there is no more work in this project running.

In addition, the repository points to a codebase that has not changed for 6 years, but NuGet releases have occurred in the interim. So something is very unclean here.

Update December 2022

In the meantime there are - thanks to the schizophrenic dictator Musk - first NuGet implementations for ActivityPub, because of Mastodon. However, it has to be said that this is all still in very early stages.