Pay per call with x402. No key, no signup.

How the 402 flow works

x402 is HTTP-native payment. Call a metered tool with no key and the gateway answers 402 Payment Required carrying standard x402 v2 payment requirements — the asset (USDC), the network (Base, chain 8453), the payee wallet, and a timeout. Your client signs an EIP-3009 transferWithAuthorization and retries. The full machine-readable manifest is at /.well-known/x402.

# A metered call with no payment returns the x402 v2 challenge.
# (The challenge machinery is live; deterministic calculators are free in
#  demo settlement today — the manifest always shows the current state.)
curl -i https://wingmanprotocol.com/tools/<paid-tool> \
  -H 'Content-Type: application/json' \
  -d '{ ...tool args... }'

HTTP/1.1 402 Payment Required
X-Payment-Required: https://wingmanprotocol.com/.well-known/x402
PAYMENT-REQUIRED: <base64 x402 v2 requirements>
Content-Type: application/json

{
  "x402Version": 2,
  "error": "payment required",
  "accepts": [{
    "scheme": "exact",
    "network": "eip155:8453",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "payTo": "0x<wallet>",
    "maxTimeoutSeconds": 300
  }]
}

Then sign the authorization and retry. In the interoperable v2 modes the signed authorization rides in the PAYMENT-SIGNATURE header; the legacy self-report mode uses X-Payment with an on-chain tx hash (the server accepts either):

# Sign the EIP-3009 authorization and retry with PAYMENT-SIGNATURE
# (x402 v2 — an x402-capable client does this for you):
curl -i https://wingmanprotocol.com/tools/<paid-tool> \
  -H 'Content-Type: application/json' \
  -H 'PAYMENT-SIGNATURE: <base64 signed EIP-3009 authorization>' \
  -d '{ ...tool args... }'

# Legacy self-settle (rpc): pay USDC on Base yourself, then send the
# on-chain receipt in X-Payment instead:
#   X-Payment: 0x<your Base tx hash>

What it costs

Deterministic calculators are free lead-gen today while x402 settlement runs in demo mode; the metered surface (real browser, multi-round research, web egress) is what the 402 flow charges for. The current state is always in the manifest.

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