1a. Web3 architecture using Coinbase Wallet

The architecture describes a non-custodial wallet (Coinbase Wallet) that interacts with decentralized applications (dApps) via Web3 protocols like WalletConnect or injected providers, and signs blockchain transactions using a locally stored private key.

🧱 Coinbase Wallet Architecture (Simplified)

graph TD
    User["User - Browser or Mobile"]
    Wallet["Coinbase Wallet App"]
    WalletUI["Coinbase Wallet Frontend - React Web App"]
    KeyMgmt["Local Private Key Storage - LocalStorage or Secure Enclave"]
    Signer["Transaction Signing - User Approves with Private Key"]
    dApp["Web3 dApps - Uniswap, OpenSea, etc."]
    WalletConnect["Web3 Protocol - WalletConnect or Injected Provider"]
    Blockchain["Blockchain Networks - Ethereum, Base, Polygon"]
    SmartContract["Smart Contracts - DeFi, NFTs, etc."]
    CoinbaseAPI["Coinbase APIs - Fiat Onramp, Token Metadata, Price Feed"]

    User --> Wallet
    Wallet --> WalletUI
    Wallet --> KeyMgmt
    Wallet --> Signer
    Wallet --> WalletConnect
    WalletUI --> CoinbaseAPI
    WalletConnect --> dApp
    dApp --> Blockchain
    Signer --> Blockchain
    Blockchain --> SmartContract

Component	Description
User Interface (UI)	The visual layer users interact with — a React-based web app or mobile frontend. Lets users view balances, send/receive assets, manage NFTs, and connect to dApps.
Coinbase Wallet App	The core application (mobile or browser extension) that combines UI, key management, transaction signing, and connectivity to Web3 apps. Acts as the “hub” for wallet functions.
1b. Local Key Storage	Private keys are generated and stored locally on the user’s device: browser local storage (desktop) or Secure Enclave/Keystore (mobile). Coinbase has no access to these keys
1c. Transaction Signing	Users sign transactions using their private keys when interacting with dApps. The signature proves wallet ownership without revealing the private key. All critical transactions (send, swap, mint) require explicit approval.
Web3 Protocol (WalletConnect / Injected Provider)	Connects the wallet to decentralized apps. The app either injects a provider (in browser) or uses WalletConnect (mobile) to allow users to authenticate and authorize transactions on external dApps.
Web3 dApps	Decentralized applications (e.g., Uniswap, OpenSea) that interact with the wallet through Web3 standards. These apps rely on smart contracts deployed to the blockchain and require wallet authentication via signed messages or transactions.
Smart Contracts	Deployed logic on-chain that performs tasks like token swaps, lending, or NFT minting. The wallet sends signed transactions to these contracts on behalf of the user.
Blockchain Networks	The wallet supports multiple EVM-compatible chains (Ethereum, Base, Polygon, Arbitrum, BNB Chain). Users can interact with dApps, manage assets, and view transaction history on these networks.
Coinbase APIs	Optional APIs used to enhance the wallet experience — includes fiat-to-crypto onramp, real-time token price data, transaction metadata, and token details. Does not provide custody or core wallet functionality.