ActivityPub: Everything to Know

By  Beluga Research September 18, 2023

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  • ActivityPub is a decentralized protocol enabling secure social networking and communication within the crypto ecosystem
  • It originated from the concept of federated social networks and became a W3C Recommendation in 2018
  • ActivityPub offers advantages such as enhanced privacy, decentralization and financial transparency
  • Disadvantages of ActivityPub include challenges such as volatility, scalability and regulatory uncertainty


ActivityPub is a decentralized protocol enabling secure social networking and communication within the crypto ecosystem. ActivityPub enables different social media platforms, services or applications to interact and share content while maintaining user privacy and control.

With ActivityPub, users on one platform can follow, share and interact with users on other platforms, fostering a more interconnected and diverse social web. This protocol has been instrumental in the development of federated and decentralized social networks, allowing users to choose the platform that aligns with personal preferences while remaining connected with others across the network.

A Brief History

ActivityPub originated from the concept of federated social networks in the early 2010s. The goal was to create decentralized alternatives to mainstream social media platforms, giving users more control over data and interactions. OStatus was an early project that enabled cross-platform communication between social networks but had limitations. In response, the W3C Social Web Working Group formed in 2014 to develop a more comprehensive and extensible protocol, leading to the creation of ActivityPub, which became a W3C Recommendation in 2018.

ActivityPub: Everything to Know

ActivityPub operates on the principles of federation and decentralization. Users can create accounts on different platforms and connect with users on other platforms. The protocol defines object types like "actors," "activities" and "objects," which are the building blocks for social interactions.

Actors represent users or entities within the network and can be individuals, organizations or bots. Each actor has a unique identifier and can perform activities such as creating posts, commenting, liking, following other actors and sharing content. Activities are represented as objects, which can be text-based messages, images, videos or more complex data structures.

ActivityPub excels at handling cross-platform interactions. For example, when an actor on one platform follows another actor on a different platform, the follow request is sent via the ActivityPub protocol. The receiving platform decides whether to accept or reject the request. This allows users to connect and interact seamlessly across platforms.

"Federated timelines" are another important aspect of ActivityPub. Each platform maintains a specific timeline of activities generated by actors on that platform. Platforms can also subscribe to activities from actors on other platforms, creating a combined timeline of activities from multiple platforms. This distributed approach ensures that users have access to diverse content and perspectives.

Getting Started

To begin using ActivityPub, users should also understand blockchain technology and decentralized networks. ActivityPub operates on existing blockchain platforms like Ethereum or Bitcoin, utilizing the associated security and consensus mechanisms. Users can interact with the protocol through compatible wallets or applications that support ActivityPub.

In ActivityPub, a "node" refers to a network participant that sends and receives activities. Each node has a unique identifier used for establishing connections and communication with other nodes. When a user creates an account on an ActivityPub-enabled platform, they become a node in the network.

Unique Aspects

ActivityPub stands out due to its decentralized nature. Unlike traditional social media platforms, where user data is stored on centralized servers controlled by a single entity, ActivityPub distributes data across multiple network nodes using blockchain technology. This decentralization offers enhanced security, censorship resistance and data privacy.

Another significant aspect is user control and ownership. Unlike traditional platforms, ActivityPub grants users complete control and ownership over activities and objects. They can choose with whom to share content and can revoke access at any time, which empowers users and gives them control over online presences.

ActivityPub also supports interoperability between platforms and applications. Users on one ActivityPub-enabled platform can seamlessly interact with users on other platforms. This fosters a more inclusive and connected social network, free from the limitations of a single platform or ecosystem. Decentralized social networks can be created that are not controlled by any one entity.

Additionally, ActivityPub introduces federated timelines, which aggregate activities from multiple users and display them chronologically. Users can see a consolidated view of activities from those they follow, regardless of the platform they are on. Federated timelines promote discoverability and connections with new content and users from different platforms.


  • Enhanced Privacy - ActivityPub leverages blockchain's cryptographic features to enhance privacy. Transactions within the network are pseudonymous, allowing users to maintain privacy while engaging in financial activities.
  • Decentralization - ActivityPub is decentralized, unlike traditional social media platforms that are controlled by a central authority. This reduces the risk of data breaches and censorship, making the system more resilient.
  • Financial Transparency - Integrating cryptocurrency into ActivityPub introduces a new level of financial transparency. All transactions are recorded on the blockchain, accessible to all network participants, and this transparency fosters trust and helps prevent fraudulent activities.
  • Micropayments and Tipping - ActivityPub enables micropayments and tipping within social media platforms. Users can easily send small amounts of cryptocurrency to reward content creators or show appreciation, providing new opportunities for monetization and incentivizing quality content creation.
  • Borderless Transactions - ActivityPub significantly reduces the limitations and fees associated with cross-border transactions. The decentralized nature of the network allows seamless and cost-effective transactions, facilitating financial activities between users from different countries without intermediaries.


  • Volatility - ActivityPub, like other cryptocurrencies, is subject to price volatility. Fluctuations in value pose risks for users engaging in financial activities within the network, potentially discouraging adoption.
  • Scalability Challenges - As the number of users and transactions in the ActivityPub network grows, scalability becomes a concern. Blockchain networks face limitations in transaction processing speed and capacity, leading to longer confirmation times and higher fees during high network congestion. Scalability solutions such as layer 2 protocols are being developed to address these challenges.
  • Regulatory Uncertainty - Cryptocurrency regulations vary across jurisdictions, posing compliance challenges for ActivityPub. Users and platform operators must stay informed about applicable regulations to ensure compliance and avoid legal consequences.
  • Energy Consumption - Cryptocurrency "mining," or the process of solving mathematical puzzles to add blocks to the blockchain, including that used in ActivityPub, consumes significant energy. This raises concerns about the sustainability of cryptocurrency networks, prompting the exploration of energy-efficient consensus mechanisms like proof-of-stake (PoS).
  • User Experience - While ActivityPub offers exciting possibilities, the user experience may be unfamiliar and challenging for newcomers. Concepts like "private keys," "wallets," and "transaction confirmations" involve a learning curve. Therefore, simplifying the user experience and providing intuitive interfaces can onboard more users and make the technology accessible to a wider audience.