spend.md

Spend Tokens

Spenders (apps) spend tokens by calling SpendPermissionManager.spend with their spend permission values, a recipient, and an amount of tokens to spend.

Spenders may want to batch this call with an additionally prepended call to approve their permission via user signature or the convenience function SpendPermissionManager.spendWithSignature. After a permission is approved, it is cheaper to avoid re-validating the signature and approval by just calling SpendPermissionManager.spend for repeated use.

When executing a spend, SpendPermissionManager calls CoinbaseSmartWallet.execute with either a call to transfer native or ERC-20 tokens to the recipient. Only these two kinds of calls are allowed by the SpendPermissionManager on a CoinbaseSmartWallet for reduced risk.

sequenceDiagram
    autonumber
    participant S as Spender
    participant PM as Permission Manager
    participant A as Account
    participant ERC20

    alt
    S->>PM: approveWithSignature
    Note over PM: validate signature and store approval
    else
    A->>PM: approve
    end
    S->>PM: spend
    Note over PM: validate permission approved <br> and spend value within allowance
    PM->>A: execute
    Note over PM,A: transfer tokens
    alt token is ERC-7528 address
        A->>S: call{value}()
        Note over A,S: transfer native token to spender
    else else is ERC-20 contract
        A->>ERC20: transfer(spender, value)
        Note over A,ERC20: transfer ERC-20 to spender
    end

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