BNB Smart Chain (BSC)

EVM chain

BNB Smart Chain

BSC processes more daily transactions than any EVM chain except Ethereum. Its stablecoins lack EIP-3009, so the facilitator settles via Permit2. Payers need BNB only for the one-time Permit2 approval (~$0.001).

Permit218 decimals

Network ID

Why BSC Is Different

Permit2 is Uniswap's canonical token approval contract, deployed at the same address on every EVM chain. It works with any ERC-20 regardless of whether the token implements EIP-3009 or EIP-2612. The upstream @x402/evm SDK routes Permit2 payloads automatically when the facilitator signals assetTransferMethod: "permit2".

Token Details

Settlement Model

The facilitator returns scheme: "exact" with extra.assetTransferMethod: "permit2" for BSC. Settlement uses two contracts:

• Permit2: 0x000000000022D473030F116dDEE9F6B43aC78BA3
• x402ExactPermit2Proxy: 0x402085c248EeA27D92E8b30b2C58ed07f9E20001

How it works:

1. Payer approves the Permit2 contract for the token (one-time, ~$0.001 BNB). The facilitator can relay this transaction via the erc20ApprovalGasSponsoring extension.
2. Payer signs an EIP-712 PermitWitnessTransferFrom authorization (off-chain, no gas).
3. Facilitator submits the authorization to the x402ExactPermit2Proxy, which settles via Permit2. Facilitator pays BNB gas.

After the one-time approval, every BSC payment requires one signature and zero BNB.

Integration:

import { wrapFetch } from '@dexterai/x402/client';
 
const x402Fetch = wrapFetch(fetch, {
  evmPrivateKey: process.env.EVM_PRIVATE_KEY,
  preferredNetwork: 'eip155:56',
});
 
// BSC payment handled automatically via Permit2
const response = await x402Fetch('https://api.example.com/protected');

No BSC-specific code is needed. The standard @x402/evm package and the @dexterai/x402 SDK both handle Permit2 routing when the facilitator signals it.

Best Fit

• merchants accepting payment from BSC-native users holding USDT or USDC
• agents operating on BSC that need programmatic payments with minimal gas overhead
• teams that want standard SDK compatibility with zero BSC-specific code

Quick Support Check

curl -s https://x402.dexter.cash/supported | jq '.kinds[] | select(.network == "eip155:56")'

Validate Before Shipping

1. Confirm BSC appears in /supported with scheme: "exact" and extra.assetTransferMethod: "permit2".
2. Confirm you are using eip155:56 as the network identifier.
3. Confirm amounts use 18 decimals (not 6).
4. Test POST /verify and POST /settle with a real BSC-targeted payment.

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