Mastodon vs. Nostr: Unpacking the Open Source Social Protocols

Mastodon vs. Nostr: Unpacking the Open Source Social Protocols

Bobby Shell
Bobby Shell

August 4, 2023

Mastodon and Nostr are two prominent open-source social network protocols designed to enable decentralized communication across the Internet. Despite their shared objectives, they each present unique functionalities and designs. In this blog post, we'll dive into the key differences between these two protocols.

1. Federation vs. Peer-to-Peer Structure

The most fundamental difference lies in their network structure. Mastodon utilizes a federated network model, where independent servers (called 'instances') communicate. Users can join any instance, and interact with users from other instances, creating a network of connected but independently operated communities. The instance you join determines your default community and the specific moderation policies you are subject to.

In contrast, Nostr adopts a peer-to-peer (P2P) network design. Every user uses their private key connected to a client service (iris, damus, amathyst, etc.)  to send a message to a relay to propagate it to the wider network. Those running relays can block specific nostr pubkeys if they wish, but unlike Mastadon, you can use your nostr private key anywhere that is nostr compatible. You can connect to a different relay, or use a different client any time and take your identity and entire activity history. 

In contrast, Nostr adopts a client-relay design. Relays act as servers for Nostr, providing a platform for clients to transmit messages. They store messages and broadcast them to all other connected clients. Clients are the apps used to access and interact with the protocol. They listen to events broadcasted by the relays they’re connected to and broadcast your events (like posting a note). Users are represented by public keys and their respective private key signs every user event.  Relays can block public keys, but unlike Mastodon, you can connect to different relays or use different clients at any time and take your identity and entire history of activity with you. Another key difference between Nostr and Mastodon is that, unlike instances, relays don’t communicate with each other. Therefore, Alice must share at least one common relay with Bob to view Bob's posts.

2. Identity & Moderation

On Mastodon, your identity is tied to the instance you join. Each instance has its moderation policies, and admins can block harmful users or instances. This way, Mastodon provides moderation and control against spam and abuse.

Nostr, however, does not link your identity to a specific server. You have a public key, which forms the basis of your identity, and you broadcast your messages to the network. Moderation, filtering, and blocking are all client-side. You can decide who to listen to and who to block based on your preferences.

3. Protocol Complexity & Flexibility

Mastodon is built on top of a protocol called “ActivityPub.” It provides a client to server support for creating, updating, and deleting content and federated server-to-server support for delivering notifications and content between instances. The complexity offers feature richness but at the cost of scalability and simplicity.

Nostr, on the other hand, focuses on simplicity. The simplest open protocol can create a censorship-resistant global “social” network.. This simplicity allows Nostr to be flexible and easily adapted for applications beyond social networking, like microblogging, bulletin boards, or decentralized comment systems.

4. Content Durability

In Mastodon, the content is stored on the instances. If an instance goes offline, its exclusive content is lost unless it has been federated (shared) with other instances.

Conversely, Nostr doesn't store content on a central server. Every message in the Nostr network is a self-contained note signed with the author's private key. Any client that receives a note can store it for as long as they want and share it with any other client. This makes content in the Nostr network more durable and resistant to censorship.

5. User Experience

Mastodon has a more traditional social media experience with profiles, posts, replies, hashtags, and timelines. It mimics mainstream platforms like Twitter but in a decentralized way.

Nostr, due to its simplicity and flexibility, doesn't provide a standard user experience. It provides the underlying structure for various applications, and the user experience heavily depends on the specific client application you use to interact with the Nostr network.


Mastodon and Nostr represent different approaches to decentralization. Mastodon mirrors the functionality of traditional social media platforms in a federated manner, allowing instances to govern their communities with their own rules while still enabling cross-instance communication. In comparison, Nostr emphasizes user autonomy with a simpler, more flexible protocol that can be adapted for many different purposes.

Each has its strengths and weaknesses, and the choice between them will largely depend on the specific needs and values of the user. Mastodon may be more suitable for those seeking a more familiar social networking experience with some level of moderation. At the same time, Nostr may appeal to those prioritizing total decentralization, flexibility, and individual control over content and moderation.

Remember that, despite their differences, both protocols aim to promote decentralized communication and put control back into users' hands. In an era of increasing concerns over data privacy and control, these open-source protocols could potentially reshape the future of online social interactions.

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