Circle Nanopayments

Gas-free, sub-cent USDC over the x402 exact scheme, settled by Circle Gateway in batches.

Nanopayments are A-Identity’s second x402 rail. Where our on-chain rail settles each call as a real USDC transfer, Nanopayments settle off-chain and in batches: the buyer signs an EIP-3009 authorization (zero gas), Circle Gateway verifies and credits it instantly, and the on-chain settlement is netted across many payments into a single transaction. That is what makes true sub-cent payments economical for high-frequency agent traffic.

It is the same x402 negotiation, using Circle Gateway’s GatewayWalletBatched scheme. Permissionless on Arc testnet — no Circle API key.

How one nanopayment works

1. Deposit once

   The buyer deposits USDC into the Gateway Wallet on Arc — a one-time on-chain transaction that establishes a spendable Gateway balance. (This is the same deposit Circle Gateway uses.)

2. 402 Payment Required

   The buyer requests a paid resource. The seller answers 402 with the GatewayWalletBatched requirements (network eip155:5042002, USDC, the verifying contract).

3. Sign off-chain (zero gas)

   The buyer signs an EIP-3009 TransferWithAuthorization against the Gateway contract and retries with the signed payload. No gas, no on-chain transaction.

4. Settle and serve

   The seller submits the authorization to Circle Gateway, which verifies it, credits the seller’s balance, and returns a settlement id. The resource is served immediately; Gateway batches the on-chain settlement.

x402 on-chain vs Nanopayments

A-Identity ships both rails, and says which is which:

	On-chain x402	Nanopayments
Where	mcp/src/x402.ts	mcp/src/nanopay.ts
Settlement	A real USDC transfer per call, verified on-chain	Off-chain EIP-3009 auth, batched on-chain by Gateway
Gas	Paid per call (USDC on Arc)	Zero for buyer and seller
Proof	An arcscan tx hash	A Gateway batch settlement id
Best for	Provable, standalone settlement	High-frequency, sub-cent streams

Verified live on Arc testnet: an EIP-3009 authorization signed off-chain settled through Circle Gateway with success: true, a real batch settlement id, and the buyer’s Gateway balance debited by the paid amount — on both the local and the live production backend. SDK: @circle-fin/x402-batching.

Why it matters for agents

An AI agent paying per model response, per dataset row, or per API call cannot afford gas on every micro-transaction. Nanopayments make streaming, sub-cent, machine-to-machine payments economical — the buyer’s own key still authorizes every payment, so authority stays bounded.

The x402 standard

Both rails share the same 402 negotiation. See how the on-chain rail verifies and binds each payment.