Farcaster

Farcaster is a decentralized social protocol for public short messages called casts, profiles, follows, reactions, and Ethereum address verification. The same Farcaster account can appear in more than one compatible app, so changing clients does not require rebuilding a separate audience.

An FID separates account ownership from app keys

Creating an account assigns a Farcaster ID, or FID, to an Ethereum address through onchain registration. A working account also needs a username, storage, and a key that can sign social messages.

The address that owns the account is distinct from the keys granted to social apps. An app can therefore publish signed casts without receiving the ownership key. A recovery address can restore control when a separate wallet used for social activity is lost, making recovery settings meaningful rather than cosmetic account details.

Signed casts replicate through Hubs

Casts, reactions, follows, profile data, and address verifications are separate signed message types. Hubs share those messages across a peer-to-peer network, allowing compatible clients to read the same basic content history and social graph.

The network is eventually consistent, so a newly submitted cast, reaction, or follow does not become visible everywhere at the same moment. Deleting a message publishes a deletion message and leaves a tombstone; that deletion still occupies storage until newer activity pushes it out.

Storage rent limits message history

Accounts rent storage for casts, reactions, follows, profile data, and verifications. Each type has its own capacity, and the oldest message of an over-capacity type is pruned unless the account adds storage.

An account can retain its identity while losing accumulated messages if storage expires after its grace period. Farcaster channels provide topical public feeds with hosts who can pin or hide casts, block people from posting, and appoint co-hosts. Mini Apps then add authenticated interactive experiences inside compatible feeds rather than making every action leave the social client.