Farcaster Hubs

How do you develop on top of the Farcaster protocol? Dive in. Focus is on giving you just as much documentation as needed as well as conceptual overviews and examples. We link out to detailed project documentation where used.

What is a Farcaster Hub?

Farcaster works by some servers storing history of the social network and one being able to add new history (e.g. posts, likes, follow, …) to them.

These servers are called hubs. If you are familiar with blockchains, you may think of them as nodes.

Hubs verify that the rules of the social protocol are followed. How the social protocol differs from the social network you ask? The social network is the content and relationships between accounts. Say I post something, you follow me or maybe someone likes a post that is part of the social network.

But to verify that only you as the owner of the account or applications that you authorize may post is defined in the social protocol. To verify these rules and run the underlying social protocol that the social network is built on top of we utilize Hubs.

A hub is software running on a server to verify the rules of the social protocol while also storing the data of the social network.

Many people and companies run hubs, which creates a distributed network of different parties verifying the social protocol rules are adhered to. Anyone can run a hub and be part of verifying rules as well as storing or adding data.

Where do Hubs fit within the greater Farcaster architecture

Hubs are the base layer, the ground truth. Besides identity (e.g. your account - FID) which is stored and verified on the blockchain (Optimism Mainnet), Hubs store and verify everything going on in the Farcaster protocol.

Everything we build on top of Farcaster relies on people running hubs and hubs being available.

You build APIs on top of data from Hubs being replicated and enriched into databases, that then serve the API queries.

You use Hubs to verify signatures and make sure that a message you see is valid.

For a message to be accepted, the fid must be registered in the Id registry, and signed with a valid signer present the Key registry, and the fid must have enough storage allocated in the Storage registry.

As stated they are the source of truth.