Circle Nanopayments Go Live on OP Mainnet With Gas-Free USDC

The launch introduces what Circle calls the first multichain payment gateway built for AI agents. It uses the x402 protocol, an open HTTP-native payment standard, so that machines can pay for services without accounts, cards, or sessions.

How Circle Nanopayments Work

Circle Nanopayments avoid per-transaction gas fees through a batching model built on Circle Gateway. Users first deposit USDC into a non-custodial Gateway smart contract. From there, agents sign lightweight EIP-3009 authorizations off-chain for each payment.

The system then verifies each signature instantly inside a Trusted Execution Environment and deducts the amount from an off-chain balance. Thousands of these authorizations get aggregated into a single on-chain batch transaction. Gas costs apply only at the batch level.

This means individual payments as small as one-millionth of a dollar carry no gas cost for the sender. According to Circle’s developer documentation, the approach delivers instant verification with periodic on-chain settlement.

What the x402 Protocol Does

The x402 protocol revives the HTTP 402 “Payment Required” status code. The code was reserved in 1999 but never widely used. Now the x402 Foundation, operating under the Linux Foundation, has turned it into a standard for machine-to-machine payments.

When an AI agent sends a request to a server, the server can respond with a 402 status code and a JSON payload. That payload specifies the amount, token, and payment instructions. The agent signs the authorization and retries the request with the signed payload in the headers.

A facilitator verifies and settles the transaction on-chain. Circle Nanopayments acts as the high-frequency backend compatible with x402 v2. Analyst Andrew Clews noted on X that x402 has already processed approximately $48 million in volume, mostly on Base.

Circle Nanopayments on OP Mainnet

The Gateway contracts are live on Optimism. The GatewayWallet contract sits at 0x77777777Dcc4d5A8B6E418Fd04D8997ef11000eE on OP Mainnet. A related contract is deployed at 0x2222222d7164433c4C09B0b0D809a9b52C04C205.

Because Nanopayments batches transactions off-chain, individual micropayments do not appear as separate on-chain transactions. Early batch settlements will show up on Optimistic Etherscan as calls from the Gateway contracts.

OP Mainnet currently holds $356.22 million in DeFi TVL and roughly $588 million in stablecoin market cap, according to DefiLlama. The OP token traded at approximately $0.12 on the announcement day, with no immediate price spike from the launch.

What Circle’s CEO Said

Circle co-founder and CEO Jeremy Allaire announced the launch on X on April 29. He called it “the first multichain payment gateway for agents, across 11 chains, USDC + x402 support for sellers and buyers, and support for 0.000001 sized nanopayments.”

Allaire described the system as “an open and permissionless protocol on the internet.” Circle’s official account added that Nanopayments gives builders “a new financial rail for agentic economy” with gas-free USDC transfers, instant verification, and unified liquidity across supported chains.

Optimism’s official account amplified the announcement on April 30, confirming that “AI agents pay for services autonomously via x402, no accounts or cards.”

Community Reaction and Sentiment

Sentiment on X leaned strongly positive among builders and analysts. Builders highlighted pay-per-API-call and metered AI compute as use cases. Some teased early integrations with projects like Arc.

The broader narrative frames this as foundational infrastructure for the “agentic economy.” Both retail users and industry insiders described the launch as infrastructure that unlocks capabilities that were not possible before.

Not everyone is fully convinced, though. Testnet coverage from outlets like The Defiant and CryptoTimes raised questions about whether enough AI-agent usage exists to justify the infrastructure. Some commentary questioned if real demand has arrived yet.

Open Questions and Risks

Several details remain unclear. Circle has not disclosed the exact fee structure for merchants or facilitators using batch settlement. The precise throughput limits per batch or per day are also unknown.

No public security audit reports for the TEE and batching logic have been announced. It is also unclear which specific AI agents or apps are already live on mainnet beyond teased integrations.

Circle’s central role as the USDC issuer raises potential centralization concerns. Competing approaches include Tempo and various direct wallet SDKs. The system also faces the fundamental question of whether sub-cent AI-agent payment demand will materialize at scale.

Timeline of Key Events

The path to launch started in September 2025, when Coinbase and Cloudflare first announced the x402 protocol. Circle launched Nanopayments on testnet on March 10, 2026, followed by a technical deep-dive blog on March 20.

The mainnet launch on April 29 brought gas-free USDC down to $0.000001 across 11 chains. Circle has supported native USDC on Optimism since at least 2023, so the OP Mainnet integration builds on an existing relationship.

Prior micropayment efforts in crypto, including Bitcoin’s Lightning Network and Superfluid’s streaming payments, took different approaches. None combined HTTP-native x402, EIP-3009 batching, and unified stablecoin liquidity at this scale.

What Comes Next for Circle Nanopayments

The immediate test is adoption. Circle has built the rails, but the system needs AI agents and developers to integrate it into production workflows. Early x402 volume on Base suggests interest, though mainnet traction on OP Mainnet and other chains will be the real measure.

Builders can start using the Circle Gateway developer docs to integrate Nanopayments into their applications. The infrastructure for machine-to-machine payments at scale is now live. Whether the machines show up to use it is the next chapter.