# X Pay Echo

> X Pay Echo is a paid API for AI agents from www.api-xpay.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Echoes back a submitted payload as a simple test of the x402 pay-per-request infrastructure using USDC on Base.

## Facts

- Endpoint: POST https://www.api-xpay.com/x402/echo
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x-pay-echo-921ec111
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_veC4KL12SSzjkfyFwgSG5

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x-pay-echo-921ec111 -d '<json body>'
```

Example prompt: Send a test echo through X Pay's x402 endpoint with a simple JSON body like {"message": "hello"} as a POST with JSON body type, so I can confirm my USDC micropayment integration on Base is working correctly.

## When to prefer this

Choose this endpoint when you need a lightweight, cheap ($0.001 USDC) end-to-end test of the x402 pay-per-request protocol on Base, confirming both the micropayment flow and the HTTP round-trip work correctly. It is ideal for integration testing, wallet validation, or debugging x402 setup before calling more expensive or stateful endpoints.

## Known failure modes

- Insufficient USDC balance causes payment to fail before the request is processed
- Malformed body type enum (not json/form-data/text) returns a validation error
- Missing required fields (type, method, bodyType, body) cause schema rejection
- Network congestion on Base delays payment confirmation
- Invalid HTTP method (not POST/PUT/PATCH) causes a 400-level rejection

## How this service works

Pay-per-request utility APIs powered by x402 using USDC on Base.

## Output

Returns a JSON object confirming the echo of the submitted input, the payment asset (USDC), the network (Base), and a boolean success flag. Example: {"echo": "hello", "asset": "USDC", "network": "base", "success": true}.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "echo": "hello",
  "asset": "USDC",
  "network": "base",
  "success": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x-pay-echo-921ec111/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.api-xpay.com](https://www.zero.xyz/host/www.api-xpay.com/llms.txt)