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

# Pay External Service

> Pay an external API via the x402 protocol (HTTP 402). MIDAS handles payment signing and settlement automatically.

## Overview

The x402 endpoint lets your agent pay any external service that supports the [x402 protocol](https://x402.org) (HTTP 402 Payment Required). MIDAS acts as a proxy:

1. Makes the HTTP request on your behalf
2. If the service returns `402 Payment Required`, MIDAS parses the payment requirements
3. Signs an EIP-3009 `transferWithAuthorization` using your agent's Base wallet
4. Retries the request with the `PAYMENT-SIGNATURE` header
5. Returns the service response to you

Protocol fees (1.5%) apply. Transaction limits based on your reputation tier apply.

## Request

<ParamField body="url" type="string" required>
  The target URL to call. Must be a valid HTTPS URL.
</ParamField>

<ParamField body="method" type="string" default="GET">
  HTTP method: `GET`, `POST`, `PUT`, `PATCH`, or `DELETE`.
</ParamField>

<ParamField body="headers" type="object">
  Optional headers to forward to the target service.
</ParamField>

<ParamField body="body" type="string">
  Request body for POST/PUT/PATCH requests. Max 50KB.
</ParamField>

## Example

```bash theme={null}
curl -X POST https://api.midasprotocol.org/x402/pay \
  -H "Authorization: Bearer pp_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://api.example.com/premium-data",
    "method": "GET"
  }'
```

## Response (no payment needed)

If the target service does not require payment, the response is proxied directly:

```json theme={null}
{
  "success": true,
  "statusCode": 200,
  "headers": { "content-type": "application/json" },
  "body": "{\"data\": \"...\"}"
}
```

## Response (payment settled)

If the service returned 402 and MIDAS paid successfully:

```json theme={null}
{
  "success": true,
  "statusCode": 200,
  "headers": { "content-type": "application/json" },
  "body": "{\"data\": \"premium content\"}",
  "payment": {
    "amount": "0.01",
    "asset": "USDC",
    "network": "eip155:8453",
    "payTo": "0x...",
    "protocolFee": "0.00015"
  }
}
```

## Response (payment failed)

```json theme={null}
{
  "success": false,
  "statusCode": 402,
  "headers": {},
  "body": "[...]",
  "error": "No compatible payment requirement found. MIDAS supports exact scheme on Base (eip155:8453) with USDC."
}
```

## Supported Payment Schemes

| Scheme             | Network              | Asset | Status    |
| ------------------ | -------------------- | ----- | --------- |
| `exact` (EIP-3009) | Base (`eip155:8453`) | USDC  | Supported |

## Prerequisites

* Your agent must have a **blockchain wallet** (automatically created at registration)
* Sufficient **USDC balance** in your internal wallet
* Transaction must be within your **reputation tier limit**

## How It Works (Technical)

1. MIDAS makes the initial HTTP request
2. On 402 response, parses `PAYMENT-REQUIRED` header or response body
3. Selects a compatible payment requirement (exact scheme, Base network, USDC)
4. Decrypts the agent's private key and signs an EIP-3009 `TransferWithAuthorization`
5. Retries with both `X-PAYMENT` and `PAYMENT-SIGNATURE` headers
6. On success, debits the agent's internal USDC balance + 1.5% protocol fee