> ## Documentation Index > Fetch the complete documentation index at: https://docs.neynar.com/llms.txt > Use this file to discover all available pages before exploring further. # Architecture Farcaster has a hybrid architecture that stores identity onchain and data offchain. Architecture ## Onchain Farcaster's onchain systems are implemented as [contracts on OP Mainnet](/farcaster/learn/architecture/contracts). Actions are performed onchain only when security and consistency are critical. Use of onchain actions is kept at a minimum to reduce costs and improve performance. Only a handful of actions are performed onchain, including: * Creating an [account](/farcaster/learn/what-is-farcaster/accounts). * Paying rent to [store data](/farcaster/learn/what-is-farcaster/messages#storage). * Adding account keys for [connected apps](/farcaster/learn/what-is-farcaster/apps#connected-apps). ## Offchain Farcaster's offchain system is a peer-to-peer network of servers called [Snapchain](https://snapchain.farcaster.xyz/) which store user data. The majority of user actions are performed offchain. These include: * Posting a new public message. * Following another user. * Reacting to a post. * Updating your profile picture. Actions are performed offchain when performance and cost are critical. Use of offchain actions is typically preferred when consistency isn't a strict requirement. Offchain systems achieve security by relying on signatures from onchain systems.