Backend for Carmel

Architecture Overview

The backend is designed to be infinitely scalable – limited only by GCP credits :)

The Listener module observes all NFT-related contracts on Solana and publishes a Pub/Sub message for each relevant event.

The Processor module is hosted as a Cloud Run instance. This way it scales relative to on-chain activity. It currently processes 50-70 tx/sec, which accounts for all NFT activity on-chain.

The WalletSync module listens for Pub/Sub messages which are sent by the frontend if an end-user requests any information not already cached in the Firestore DB.

sequenceDiagram
    participant Listener
    participant Processor
    participant WalletSync
    participant Webapp
    Listener->>Processor: Relevant tx published
    loop ProcessSignature
        Processor->>Processor: Parse+cache tx
        Processor->>WalletSync: Parse+cache adjacent wallets
        Processor->>Processor: Parse+cache adjacent mints
        WalletSync->>Processor: Parse+cache adjacent mints
    end
    Webapp->>WalletSync: TX/Wallet UI requested
    WalletSync->>Processor: Parse+cache adjacent txs

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Docker images are setup for each of the three components in /docker. A GCP project is required to use the Pub/Sub and Firestore functionality (place Google Application Credentials json file in ./private/gcloud-credentials.json