venice-x402

Venice x402 (wallet credits)

x402 is Venice's wallet-based payment flow. Pay per request with USDC on Base, no account required. Three admin endpoints plus the protocol-level 402 response returned by every inference endpoint.

For the SIWE header format itself, see venice-auth.

Pay with a wallet: end-to-end

1. Call an inference endpoint with no balance → 402

Any inference endpoint (e.g. POST /chat/completions) returns a 402 with structured topUpInstructions and siwxChallenge when the wallet balance is too low. The PAYMENT-REQUIRED response header carries the x402 v2 paymentRequired object (base64-encoded JSON containing x402Version, error, resource, accepts[], and optional extensions) — it is not the same payload as the 402 body, which is a richer balance/top-up document.

{
  "error": "Payment required",
  "code": "PAYMENT_REQUIRED",
  "message": "Insufficient x402 balance",
  "suggestedTopUpUsd": 10,
  "minimumTopUpUsd": 5,
  "supportedTokens": ["USDC"],
  "supportedChains": ["base"],
  "topUpInstructions": {
    "step1": "POST /api/v1/x402/top-up with no payment header to get payment requirements",
    "step2": "Sign a USDC transfer authorization using the x402 SDK (createPaymentHeader)",
    "step3": "POST /api/v1/x402/top-up with the signed X-402-Payment header",
    "receiverWallet": "<RECEIVER_WALLET_ADDRESS>",
    "tokenAddress": "<USDC_TOKEN_ADDRESS>",
    "tokenDecimals": 6,
    "network": "eip155:8453",
    "minimumAmountUsd": 5
  },
  "siwxChallenge": {
    "info": { "domain": "api.venice.ai", "statement": "Sign in to Venice AI", ... },
    "supportedChains": ["eip155:8453"]
  }
}