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

# Merchant Introduction

> Learn how to sell services with x402.

## Monetize your API with x402

x402 lets you monetize HTTP APIs and content with on-chain payments, while keeping your existing server stack.

Benefits:

✅ Merchants don't pay network fees.\
✅ Customers don't pay network fees.\
✅ Payment settles in \< 1 second.\
✅ Universal compatibility -- if it speaks HTTP, it speaks x402.

## Architecture at a glance

<img src="https://mintcdn.com/payai/4LHfgOPrYQU9GWE8/images/x402-sequence-diagram.svg?fit=max&auto=format&n=4LHfgOPrYQU9GWE8&q=85&s=f9a5356f8d04bfa03987fe5a8d8d0db4" alt="x402 sequence diagram" width="1992" height="1570" data-path="images/x402-sequence-diagram.svg" />

* **Client**: Calls your protected resource and submits payments.
* **Server (merchant)**: Advertises payment requirements, verifies payments, fulfills requests, and settles payments.
* **Facilitator**: Verifies and/or settles payments on your behalf via standard endpoints.
* **Blockchain**: Where payments are executed and confirmed.

## Getting started

Select one of the quickstart examples, or read the [reference](/v1/x402/reference) for more details.

<Tabs>
  <Tab title="TypeScript">
    <CardGroup>
      <Card title="Express" href="/v1/x402/servers/typescript/express" icon="server">
        Quickstart for building an x402-enabled server with Express.
      </Card>

      <Card title="Hono" href="/v1/x402/servers/typescript/hono" icon="server">
        Quickstart for building an x402-enabled server with Hono.
      </Card>

      <Card title="NextJS (coming soon)" href="/v1/x402/servers/typescript/nextjs" icon="server">
        NextJS server quickstart is coming soon.
      </Card>
    </CardGroup>
  </Tab>

  <Tab title="Python">
    <CardGroup>
      <Card title="FastAPI" href="/v1/x402/servers/python/fastapi" icon="server">
        Quickstart for building an x402-enabled server with FastAPI.
      </Card>

      <Card title="Flask" href="/v1/x402/servers/python/flask" icon="server">
        Quickstart for building an x402-enabled server with Flask.
      </Card>
    </CardGroup>
  </Tab>
</Tabs>

## Facilitator URL

The PayAI facilitator URL is `https://facilitator.payai.network`.

## x402 reference

For a deeper dive into message shapes, headers, verification and settlement responses, see the [x402 Reference](/v1/x402/reference).

## Need help?

<Card title="Join our Community" icon="discord" href="https://discord.gg/eWJRwMpebQ">
  Have questions or want to connect with other developers? Join our Discord server.
</Card>