webfed

Webfed, short for web federation, is an umbrella term for technologies that allow independent servers on the Web to form a unified, interoperable ecosystem. In a webfed model, users and content reside on distinct servers (instances) but can interact across boundaries using common protocols. This architecture enables features such as following, sharing, and messaging across services without centralized hosting.

The most notable standard within this space is ActivityPub, a W3C Recommendation that defines how users (actors) and resources are represented and how servers exchange activities like creating and updating objects. Other components commonly used in webfed ecosystems include WebFinger for discovering user accounts, WebSub for real-time notifications, and Webmention for cross-site mentions. Authentication and authorization are often implemented with OAuth 2.0 or OpenID Connect to enable cross-service sign-on.

Webfed is closely associated with the Fediverse, a group of interoperable social networks and content platforms—such as Mastodon, Pleroma, Misskey, PeerTube, and Pixelfed—that share ActivityPub compatibility. These systems emphasize user control, portability, and community moderation, but also face challenges around moderation, spam, abuse, and scale.

Governance and standards bodies, including the W3C and IETF, maintain and standardize the protocols that enable webfed, while individual projects implement these specifications in their services. The field continues to evolve as new protocols address privacy, security, and interoperability needs.