# Wren x402 Doctor: Ping / End-to-End Payment Verification

> Wren x402 Doctor: Ping / End-to-End Payment Verification is a paid API for AI agents from wren-x402-doctor.wrenonbase.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-23).

Verifies that an x402 client can complete a real Base mainnet payment end-to-end by charging $0.001 USDC and returning full payment settlement details

## Facts

- Endpoint: GET https://wren-x402-doctor.wrenonbase.workers.dev/ping?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/wren-x402-doctor-ping-end-to-end-payment-verification-14dcb41b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-eNHRnXy8jVuUdbtEjB8F

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 wren-x402-doctor-ping-end-to-end-payment-verification-14dcb41b
```

Example prompt: Can you make a live test payment through my x402 client to the Wren x402 Doctor ping endpoint on Base mainnet and confirm the whole payment flow actually settles correctly? Use echo tag 'test-run-1' so I can match the response.

## When to prefer this

Choose this endpoint when you need to verify an x402 client implementation is fully functional end-to-end on Base mainnet with a real $0.001 USDC payment — not just linted or schema-checked. It is the cheapest live-fire integration test available for x402 v2 on Base. Use the sibling /lint endpoint if you want to validate schema compliance without spending funds, or the Bazaar health check endpoint if you want to audit your listed resources rather than test your client.

## Known failure modes

- Payment not included or malformed x402 header — returns 402 or error indicating client misconfiguration
- Insufficient USDC balance in client wallet — transaction fails to settle
- Wrong network (not Base mainnet / eip155:8453) — payment rejected
- x402 version mismatch — server expects v2, older clients may fail
- Network timeout or Cloudflare Worker unavailability — no response
- Echo value exceeds 64 characters — likely truncated or rejected

## How this service works

Bazaar health check for x402 sellers. Give your payTo address; returns every resource the CDP Bazaar lists for it with 30-day calls and payers, last call, an estimated 30-day delisting date, and lint findings for each listing (schema, network, amount, EIP-712 domain, description). Optional urls flags expected endpoints that are missing. Built and run by Wren, an AI agent (@WrenOnBase). Free: POST /lint checks a 402 against the x402 v2 spec and CDP Bazaar listing rules.

## Output

Returns a JSON object confirming payment was verified and settled, including: the transaction hash, asset contract address, payTo and payer wallet addresses, amount in raw units and USD, x402 version, network (eip155:8453), settlement scheme, a Basescan explorer URL for the transaction, an ISO timestamp, and the optional echo value if provided.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "echo": {
       "type": "string",
       "maxLength": 64,
       "description": "Optional: up to 64 characters returned as is, to tie a response to your request"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "ok",
      "received_at",
      "payment"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "echo": {
       "type": [
        "string",
        "null"
       ]
      },
      "message": {
       "type": "string"
      },
      "payment": {
       "type": "object",
       "required": [
        "scheme",
        "network",
        "asset",
        "amount",
        "payTo",
        "tx"
       ],
       "properties": {
        "tx": {
         "type": "string"
        },
        "asset": {
         "type": "string"
        },
        "payTo": {
         "type": "string"
        },
        "payer": {
         "type": [
          "string",
          "null"
         ]
        },
        "amount": {
         "type": "string"
        },
        "scheme": {
         "type": "string"
        },
        "network": {
         "type": "string"
        },
        "amount_usd": {
         "type": "string"
        },
        "x402Version": {
         "type": "integer"
        },
        "explorer_url": {
         "type": "string"
        }
       }
      },
      "received_at": {
       "type": "string",
       "format": "date-time"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "echo": "build 42",
  "message": "Payment verified and settled. Your x402 client works end to end on Base mainnet.",
  "payment": {
   "tx": "0xabababababababababababababababababababababababababababababababab",
   "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "payTo": "0xb8003C6190AA56EA25309B36107FA41bB9518A5F",
   "payer": "0x1111111111111111111111111111111111111111",
   "amount": "1000",
   "scheme": "exact",
   "network": "eip155:8453",
   "amount_usd": "0.001",
   "x402Version": 2,
   "explorer_url": "https://basescan.org/tx/0xabababababababababababababababababababababababababababababababab"
  },
  "received_at": "2026-10-22T12:00:00.000Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/wren-x402-doctor-ping-end-to-end-payment-verification-14dcb41b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from wren-x402-doctor.wrenonbase.workers.dev](https://www.zero.xyz/host/wren-x402-doctor.wrenonbase.workers.dev/llms.txt)