ActivityPub is the new standard for connecting social networks together on the social web. This open, decentralized social networking protocol defines an API for sharing activities to a social network and a procedure that servers use to distribute those activities to a subscriber's feed. With this book, you'll learn how to assemble ActivityPub-enabled clients for making new kinds of social apps on top of existing networks and build ActivityPub servers that create new human or automated accounts on the social web. With those skills under your belt, you can explore other applications of this publish-subscribe technology: content management systems, internet of things, and enterprise automation. With hands-on examples and in-depth knowledge from Evan Prodromou, one of the authors of the protocol, this is the ActivityPub handbook that every social software hacker needs. Learn what the social web is and what ActivityPub does Represent social network data in the Activity Streams 2.0 format Write a simple ActivityPub client and server Extend ActivityPub's functionality with new types Find in-depth details about the more obscure ActivityPub data structures Evan Prodromou is a coauthor of the ActivityPub protocol and the Activity Streams 2.0 data format.