# Circle Gateway Nanopayments (slim)

> Circle Gateway Nanopayments is a hosted x402 facilitator that settles gas-free USDC payments as small as $0.000001. Buyers sign offchain authorisations against a Gateway balance, and Circle settles net positions onchain in batches.

- Full: https://www.anchorterminal.com/tools/circle-gateway-nanopayments.md (~8,950 tokens) · this version ~1,830 tokens · JSON https://www.anchorterminal.com/tools/circle-gateway-nanopayments.json · canonical https://www.anchorterminal.com/tools/circle-gateway-nanopayments
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-10

**B · 67.6/100 · rank #247 of 950 · #5 in Payment & monetisation platforms · not agent-ready · confidence medium**


Assessment: A buyer with an EOA key and a seller with a wallet address can transact with no account or API key, and the settle call returns 16 documented error codes with recovery steps. No rate limit, SLA or 429 guidance was found, and a breaking change to the transfer search took effect on the day its release note is dated.

## Facts

- Kind: HTTP API · vendor: Circle · category: Payment & monetisation platforms · legal entity: Circle Technology Services, LLC · provenance 84/100
- Endpoint: `https://gateway-api.circle.com` (HTTP)
- Auth: None · pricing: Pay per use · x402: payer tooling only · licence: Proprietary hosted service under the Circle Developer Terms. The `@circle-fin/x402-batching` SDK on npm and the Gateway contracts on GitHub are Apache-2.0
- Probe metrics: not measured yet (probes haven't run)
- Flow: The buyer deposits USDC into the Gateway Wallet contract once, onchain. For each paid request the seller answers 402, the buyer signs an EIP-3009 authorisation offchain and retries, and the seller or its facilitator submits it to Gateway, which locks the buyer's funds and later settles net positions in one transaction
- API: `POST /v1/x402/settle`, `POST /v1/x402/verify`, `GET /v1/x402/supported`, `GET /v1/x402/transfers` and `GET /v1/x402/transfers/{id}` on `https://gateway-api.circle.com` (mainnet) and `https://gateway-api-testnet.circle.com` (testnet)
- SDK: `@circle-fin/x402-batching` 3.5.0, Apache-2.0, Node 18 or later, with peer dependencies `@x402/core`, `@x402/evm` and `viem`. Buyer side `GatewayClient`, `BatchEvmScheme` and `CompositeEvmScheme`. Seller side `createGatewayMiddleware` for Express, `BatchFacilitatorClient` and `GatewayEvmScheme`
- Minimum payment: $0.000001 USDC, per the docs
- Networks: Arc, Arbitrum, Avalanche, Base, Ethereum, HyperEVM, OP, Polygon PoS, Sei, Sonic, Unichain and World Chain, mainnet and testnet. Not Solana
- Signatures: EOA only. The batched path checks EIP-3009 authorisations offchain with `ecrecover`, so ERC-1271 contract signatures do not work. `validBefore` must be at least 7 days ahead per the seller quickstart and SDK source (3 days per the error reference)
- Transfer states: `received`, `batched`, `confirmed`, `completed` and `failed`. `txHash` is the batch transaction and stays null until the batch has one
- Deposit time: About 0.5 seconds on Arc, 5 to 8 seconds on Avalanche, HyperEVM, Polygon PoS, Sei and Sonic, and 13 to 19 minutes on Arbitrum, Base, Ethereum, OP, Unichain and World Chain, per the docs
- Withdrawal: `GatewayClient.withdraw` to the same chain or another supported chain. Without Circle's API, a withdrawal can be started onchain and completed after a 7-day delay
- Buyer controls: `onBeforePaymentCreation`, `onAfterPaymentCreation` and `onPaymentResponse` hooks on `GatewayClient`. The first can abort a payment above a limit. No limit is set by default
- Reconciliation: Sellers record the EIP-3009 nonce in `onAfterSettle` and look transfers up by nonce, recipient and date range with cursor pagination
- Terms: Circle Developer Terms of Service, last updated 16 September 2026, from Circle Technology Services, LLC. Gateway is a Permissionless Product under them. Privacy Policy last updated 16 September 2026 from Circle Internet Group, Inc.
- Prices: Batched nanopayment free per transaction; Crosschain withdrawal transfer fee 0.01% percentage fee; Gateway gas fee, Base as source chain $0.01 per transaction; Forwarding Service fee $0.05 per transaction

- Scores: Reliability 56, Performance pending, Schema & documentation 80, Agent ergonomics 75, Security & auth 64, Payments & pricing 80, Task success pending, Maintenance & community 77, Transparency & trust 72 · negative events -3 · total over the 7 assessed categories
- Why: Reliability, Graded as a hosted service on gateway-api.circle.com. · Schema & documentation, A public OpenAPI 3.0.3 file covers the five operations. · Agent ergonomics, The API is five operations and the buyer path is one `pay(url)` call. · Security & auth, No API key. · Payments & pricing, Payment platforms and wallets take the highest step that applies on the 40-point protocol line. · Maintenance & community, `@circle-fin/x402-batching` 3.5.0 was published on 16 September 2026, 23 days before this check, and the Gateway release notes have an entry… · Transparency & trust, The SDK is Apache-2.0 on npm and the Gateway contracts are Apache-2.0 on GitHub.
- Sources: 28, open questions: 14, both in the full twin
- Capabilities: payments.x402, payments.stablecoin
- JSON: https://www.anchorterminal.com/api/v1/tools/circle-gateway-nanopayments.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/circle-gateway-nanopayments.svg` or a link to https://www.anchorterminal.com/tools/circle-gateway-nanopayments from a page on circle.com or one of its subdomains, or the README of github.com/circlefin/evm-gateway-contracts, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Deposit on the chain you will pay from. `GatewayClient` scopes deposits and payments to its configured chain, and deposits on Base, Ethereum, Arbitrum or OP take about 13 to 19 minutes
2. Set `validBefore` at least 7 days ahead when signing by hand. The SDK uses 604900 seconds
3. Register `onBeforePaymentCreation` and abort above a cap. `pay(url)` signs whatever amount the seller's 402 response asks for
4. Call `settle` without a prior `verify`. Balance and nonce checks happen only at settle time
5. Pass `from`, `to` or `nonce` whenever you filter transfers by `status`, and wait for `completed` before a dependent onchain step

## Connect

```bash
npm install @circle-fin/x402-batching
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/circle-gateway-nanopayments

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Stripe API + MCP | A | 82.4 | payments.stablecoin, payments.x402 | https://www.anchorterminal.com/tools/stripe-mcp.min.md |
| x402 | A | 79.7 | payments.x402, payments.stablecoin | https://www.anchorterminal.com/tools/x402.min.md |
| Nevermined API + MCP | BB | 70.8 | payments.x402, payments.stablecoin | https://www.anchorterminal.com/tools/nevermined.min.md |
| Crossmint API + Docs MCP | B | 67.1 | payments.x402, payments.stablecoin | https://www.anchorterminal.com/tools/crossmint.min.md |
| ATXP | E | 42.9 | payments.stablecoin, payments.x402 | https://www.anchorterminal.com/tools/atxp.min.md |


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