> ## 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.

# Seller integration tools

> Third-party platforms that help API providers accept x402 and nanopayments.

If you run an API or online service, you can charge AI agents per request by
accepting [x402](/gateway/nanopayments/concepts/x402) payments and
[nanopayments](/agent-stack/agent-nanopayments). The third-party platforms below
help you add this support without building the integration yourself.

<Tip>
  To integrate nanopayments directly into your own server, follow the [seller
  quickstart](/gateway/nanopayments/quickstarts/seller) or the [how-to for
  adding nanopayments to an existing x402
  seller](/gateway/nanopayments/howtos/x402-seller).
</Tip>

## Third-party platforms

These independent platforms offer hosted tooling and onboarding flows for
accepting agent payments. Supported payment standards and blockchains vary by
platform, so check each platform for details.

### Blockrun

[Blockrun](https://blockrun.ai) supports x402 and nanopayments. It helps API
sellers list their services in a directory and accept payments settled in USDC
onchain.

### Proceeds

[Proceeds](https://myproceeds.xyz) supports x402, nanopayments, and the Machine
Payments Protocol (MPP). It helps sellers accept agent payments on Arc and other
blockchains.

### Sponge

[Sponge](https://paysponge.com) supports x402 and MPP, but not nanopayments. It
lets API providers accept agent payments with minimal code changes.