> ## Documentation Index
> Fetch the complete documentation index at: https://developers.circle.com/llms.txt
> Use this file to discover all available pages before exploring further.

# x402 facilitators API

> Verify and settle USDC payments over the x402 protocol using Circle's Facilitator Service or Gateway Nanopayments.

Circle's x402 facilitators let sellers accept USDC payments over the x402
protocol. Facilitator Service settles each payment onchain. Gateway Nanopayments
batches settlement for gas-free nanopayments down to \$0.000001.

## Get started

<CardGroup cols={2}>
  <Card title="API keys" icon="key" href="/api-reference/keys">
    Authenticate your requests with an API key.
  </Card>

  <Card title="x402 facilitators documentation" icon="handshake" href="/x402-facilitators">
    Learn how Circle's x402 facilitators work and compare them.
  </Card>
</CardGroup>

## Endpoint categories

<CardGroup cols={2}>
  <Card title="Facilitator Service" icon="server" href="/api-reference/facilitator-service/verify-payment">
    Verify signatures, settle payments onchain, and check payment status.
  </Card>

  <Card title="Gateway Nanopayments" icon="layer-group" href="/api-reference/gateway-nanopayments/settle-x402payment">
    Settle and verify batched x402 payments through Circle Gateway.
  </Card>
</CardGroup>

## OpenAPI specifications

The x402 facilitators API reference is generated from these OpenAPI
specifications:

* `https://developers.circle.com/openapi/facilitator-service.yaml`
* `https://developers.circle.com/openapi/gateway-nanopayments.yaml`

See [OpenAPI Specifications](/api-reference/openapi-specifications) for the full
catalog of Circle's API specs.