Multi-chain Settlement

The gateway settles paid calls in USDC over x402 on multiple networks. A paid endpoint’s 402 response lists one payment requirement per network the API is configured for; the buyer picks a network, pays on it, and the publisher is paid out on that same network.

Supported networks

Network	`network` id	USDC asset	Status
Base	`base`	`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`	Live, always on
Polygon	`polygon`	`0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359`	Live when the facilitator supports it
Arbitrum	`arbitrum`	`0xaf88d065e77c8cC2239327C5EDb3A432268e5831`	Live when the facilitator supports it

Base is never gated: it is the revenue path and is always offered. Polygon and Arbitrum are enabled only when the configured facilitator advertises a v1 exact kind for them (matched by v1 name or CAIP-2 alias). If that capability check fails for any reason, the gateway degrades to Base-only. Solana is not a settlement network on the gateway. The currently enabled set is published live in meta.settlement.networks of the discovery document at https://gateway.apiosk.com/.well-known/x402, which also lists the per-resource accepts entries with their networks.

The multi-accept 402

A paid route’s 402 now carries multiple accepts[] entries, one per network the API is configured for:

the publisher’s primary network comes first
Base is always included as a fallback
any additionally configured chains follow

Every entry prices the same resource at the same USDC amount; only network, asset, and payTo differ. All entries are EVM entries and carry the EIP-712 extra.{name,version} domain.

{
  "error": "Payment required",
  "accepts": [
    {
      "scheme": "exact",
      "network": "base",
      "maxAmountRequired": "60000",
      "resource": "https://gateway.apiosk.com/weather/current",
      "description": "Current weather conditions",
      "mimeType": "application/json",
      "payTo": "0x8f3C1a9bF2d47e05A6b21C9d8E4f70b3D5a6E210",
      "maxTimeoutSeconds": 60,
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": { "name": "USDC", "version": "2" }
    },
    {
      "scheme": "exact",
      "network": "polygon",
      "maxAmountRequired": "60000",
      "resource": "https://gateway.apiosk.com/weather/current",
      "description": "Current weather conditions",
      "mimeType": "application/json",
      "payTo": "0x8f3C1a9bF2d47e05A6b21C9d8E4f70b3D5a6E210",
      "maxTimeoutSeconds": 60,
      "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
      "extra": { "name": "USDC", "version": "2" }
    }
  ],
  "x402Version": 1
}

How buyers choose a network

Read the accepts[] array from the 402.
Pick the entry whose network you can pay on.
Sign and pay per that entry, using the EIP-712 domain in extra.
Put the network name (base, polygon, arbitrum) in the payment payload you send in x-payment: the gateway settles against the matching accepts entry.

The price is identical on every entry, so the choice is purely about which chain your payer holds USDC on.

Publisher payout wallets

Publishers configure settlement networks by attaching payout wallets in the provider portal:

attach up to 3 payout wallets per API: exactly one per network, chosen from your verified wallets
the connected wallet’s chain is auto-detected from the wallet’s active chain: Base, Polygon, or Arbitrum
wallet ownership must be verified before a wallet can be attached: the wallet signs the ownership message with an EIP-191 signature
solana is not an accepted value: the payout wallet RPC raises unsupported payout network for anything outside base, polygon, and arbitrum

Payout routing

Earnings settle to the wallet of the chain the buyer paid on: pay on Polygon, and the publisher’s Polygon wallet receives the payout; pay on Base, and the Base wallet does. The split is unchanged, 98% to the publisher, 2% platform fee, on every network.

Base fallback guarantee

If a network is unavailable, facilitator support is missing or the listing’s configuration for that chain is incomplete, the gateway falls back to Base USDC. Because every 402 always includes a Base entry, a 402 is always payable.

The SEPA Direct Debit rail is unaffected by network selection, it settles in euros on the bank side regardless of which chains a listing is configured for. See Payment Options.

Payment model: /overview/payment-model
Payment options: /guides/payment-options
Consumer guide: /guides/consumers
Bazaar discovery: /guides/bazaar-discovery

Consumers

Publishers

Connect

Boundaries

Multi-chain Settlement

Multi-chain Settlement

Supported networks

The multi-accept 402

How buyers choose a network

Publisher payout wallets

Payout routing

Base fallback guarantee

​Multi-chain Settlement

​Supported networks

​The multi-accept 402

​How buyers choose a network

​Publisher payout wallets

​Payout routing

​Base fallback guarantee

​Related links

Multi-chain Settlement

Supported networks

The multi-accept 402

How buyers choose a network

Publisher payout wallets

Payout routing

Base fallback guarantee

Related links