Polygon

Polygon is the cheapest chain for tools402. Same wire protocol as Base — EVM, EIP-3009 transferWithAuthorization, secp256k1 signing — but with gas around 5× cheaper per transfer.

#Identity

| Field | Value | |------------------|----------------------------------------------------| | CAIP-2 networkId | eip155:137 | | Chain ID | 137 | | RPC (public) | https://polygon-rpc.com | | Explorer | polygonscan.com |

#USDC

| Attribute | Value | |------------------|--------------------------------------------------------| | Contract address | 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 | | Decimals | 6 | | Issuer | Circle (native, not USDC.e) | | Verified | 2026-05-17 | | Explorer link | polygonscan.com/address/0x3c499c...3359 |

Note : tools402 only accepts Circle-native USDC on Polygon, not the bridged USDC.e (0x2791Bca…). The two are different contracts; mixing them produces a payment that won't be recognised by the facilitator.

#Buyer payment scheme

Identical to Base : exact scheme, EIP-3009 transferWithAuthorization off-chain signature, facilitator pays gas. Buyer needs only USDC on Polygon, no MATIC for gas.

text

402 quote (relevant fields)
{
  "scheme": "exact",
  "network": "polygon",
  "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
  "payTo": "0xD6E8aF2F65B4C9ACC7BF14A3096056e89E312878",
  "maxAmountRequired": "10000",
  "maxTimeoutSeconds": 60
}

#Facilitator stack (3 levels)

| Priority | Facilitator | Type | Notes | |----------|--------------------|-----------------------------|----------------------------------------------------------------| | 1 | PayAI Polygon | External, multi-chain x402 | https://facilitator.payai.network, identifies Polygon via CAIP-2 eip155:137. | | 2 | RelAI | External, gas-sponsored | Multi-chain x402 facilitator, USDC on Polygon. | | 3 | local-key-polygon| Same-chain self-signed | Server signs + broadcasts. Uses TOOLS402_FACILITATOR_KEY_POLYGON (or falls back to TOOLS402_FACILITATOR_KEY since secp256k1/EIP-155 semantics are shared with Base). |

#Marketplace recipient

text

0xD6E8aF2F65B4C9ACC7BF14A3096056e89E312878

Same address as Base — both chains share the EVM HD-derived key. Settlement to the seller happens daily at 00:00 UTC.

#Pay-on-Polygon example (curl + cast)

bash

# Same flow as Base, swap RPC + USDC contract
cast send 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 \
     "transfer(address,uint256)" \
     0xD6E8aF2F65B4C9ACC7BF14A3096056e89E312878 10000 \
     --rpc-url https://polygon-rpc.com

Then retry the original endpoint with the resulting tx hash in the X-Payment header, exactly as on Base. The marketplace decodes the chain from the network field of the receipt.