Farcaster is a protocol for building sufficiently decentralized social networks. It aims to address the issues of centralized social networks: companies controlling users’ data and relationships. Users on Farcaster have decentralized, secure, and recoverable identities. These identities, known as “Farcaster IDs” or “fids,” are autoincrement numeric values owned by an Ethereum address. A smart contract registry on Ethereum (Optimism) maps these identifiers to their corresponding key pairs. FIDs are transferable, one address can only hold one FID. Users interact on the network through messages, which can be posts (called casts), likes, updates to profiles, follows, etc. These messages are tamper-proof and self-authenticating, as they include the user’s Farcaster ID and are signed with their key pair. They can delegate the signing authority to another Ed25519 key pair, known as a signer. This allows applications to create messages on behalf of users without controlling their identity. All these activities are stored and replicated on a server called a Farcaster Hub. The social network is represented as a graph of users, content, and relationships, known as a message-graph. Farcaster Hub uses Conflict-Free Replicated Data Types (CRDTs) for decentralized data management, ensuring that updates are concurrent, permissionless, and inexpensive for developers. This design also facilitates near real-time propagation of updates across the network. To use Farcaster, users must rent storage units. Storage is rented annually and managed by the StorageRegistry contract. It’s measured in units, the pricing varies, and any user can pay for an account’s storage. [closing remarks]