ActivityPub
ActivityPub is a decentralized social networking protocol that enables different social media platforms to communicate with each other, allowing users to interact across servers. It defines a client-to-server API for creating, updating, and deleting content, and a server-to-server API for federated interactions, forming a federated social web. This protocol underpins federated social media networks like Mastodon, PeerTube, and Pixelfed, facilitating interoperability without central control.
Developers should learn ActivityPub when building or integrating social features that require decentralization, user data ownership, and cross-platform communication, such as in open-source social networks, community platforms, or privacy-focused applications. It's particularly useful for projects aiming to avoid vendor lock-in, enhance user autonomy, or comply with regulations like GDPR by enabling data portability and server independence.