Payment Flow (x402)

BonzAI uses an HTTP 402-inspired payment protocol for P2P inference. Payments are processed on Base (chain ID 8453) in ETH or USDC.

Protocol Overview

The x402 flow follows a challenge-response pattern:

1. Consumer sends inference request to provider via libp2p

2. Provider returns 402 Payment Required with amount and address

3. Consumer sends payment (ETH or signed EIP-712 authorization)

4. Consumer retries request with payment proof (tx hash)

5. Provider verifies payment on-chain, processes inference, returns result

Payment Methods

Direct ETH Payment

The simplest flow — consumer sends ETH directly:

Consumer → BonzaiPayment.payDirectETH(provider, service) + msg.value

Direct USDC Payment

Consumer approves and sends USDC:

Consumer → USDC.approve(BonzaiPayment, amount)
Consumer → BonzaiPayment.payDirect(provider, amount, service)

Pre-Deposited Balance

For faster payments, consumers can pre-deposit funds:

// Deposit
Consumer → BonzaiPayment.depositETH() + msg.value
Consumer → BonzaiPayment.deposit(usdcAmount)  // after USDC approval

// Pay from balance (no approval needed per-transaction)
Consumer → BonzaiPayment.payFromETHBalance(provider, amount, service)
Consumer → BonzaiPayment.payFromBalance(provider, amount, service)

EIP-712 Signed Authorization

For contract-mediated payments with replay protection:

1. Consumer signs an EIP-712 typed message:

   Payment(address provider, uint256 amount, uint256 nonce, uint256 expiry, string service, uint8 paymentToken)

2. Provider submits the signature to BonzaiPayment.processPayment()

3. Contract verifies signature, deducts from consumer's deposited balance, distributes funds

Domain: BonzAI x402 version 2, chain ID 8453

Fee Split

On every payment:

Recipient	Share
Provider	97.5%
Treasury	2.5%

Pricing

Providers set a pricePerToken (price per 1,000 tokens in wei) during registration.

The consumer's cost is calculated as:

estimatedTokens = (inputTokens * 3)  // input + 2x estimated output
totalAmount = ceil(estimatedTokens / 1000) * pricePerToken

Minimum: 100 tokens per request.

Self-Inference

If the consumer and provider are the same node (matching peerId), no payment is required. Self-inference is always free.

Replay Protection

• On-chain: Each (consumer, nonce) pair can only be used once

• Off-chain: Provider maintains a nonce cache in Electron Store (24h TTL, 10K entry cap)

• Expiry: Signed payments expire after 5 minutes

Supported Tokens

Token	Enum Value	Decimals
ETH	0	18
USDC	1	6

USDC on Base: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913