# Paddock Pre-Payment Endpoint Verification

> Paddock Pre-Payment Endpoint Verification is a paid API for AI agents from paddock.finance, paid per call via x402, $0.25/call, status unknown (last checked 2026-10-10).

Verifies an x402-payment endpoint before paying — checks that the payment details (seller, asset, network, price) match what you expect.

## Facts

- Endpoint: GET https://paddock.finance/api/paddock/mcp/verify-before-pay?utm_source=zero.xyz
- Price: $0.25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/paddock-pre-payment-endpoint-verification-630e5c4b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TVevUyy0o7YlyCLHQe0_g

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 paddock-pre-payment-endpoint-verification-630e5c4b
```

Example prompt: Before I pay for this API call, can you verify the endpoint https://api.example.com/some-service to make sure the seller is 0xABC123, the price is exactly $0.10 USDC, and the network is base-mainnet?

## When to prefer this

Use this endpoint when an AI agent is about to make a micropayment via the x402 protocol and needs to confirm the payment details (seller, price, asset, network) before committing funds. It is especially valuable for fraud prevention, ensuring advertised prices match reality, and building trust in automated agent payment pipelines. Prefer this over blindly calling a paid endpoint when the payment destination is not fully trusted or when the price must be confirmed programmatically.

## Known failure modes

- Endpoint URL unreachable — returns error if the target API is down or returns no 402 payment header
- Mismatch detected — returns a negative result if any expected field (price, seller, asset, network) doesn't match
- Invalid query parameters — missing required fields like endpoint_url or method returns a 400-style error
- Non-x402 endpoint — if the target endpoint doesn't support x402 payment headers, verification cannot proceed
- Network timeout — slow or unresponsive target endpoints may cause the verification call to time out

## How this service works

Paddock pre-payment endpoint verification — one-time query

## Output

Returns a structured JSON object indicating whether the endpoint's actual payment parameters (seller address, asset, network, price) match the expected values provided in the query — effectively a pass/fail pre-flight verification with detail on any mismatches.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "pay_to": {
       "type": "string"
      },
      "endpoint_url": {
       "type": "string"
      },
      "expect_asset": {
       "type": "string"
      },
      "expect_seller": {
       "type": "string"
      },
      "expect_network": {
       "type": "string"
      },
      "expect_price_usdc": {
       "type": "number",
       "minimum": 0
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/paddock-pre-payment-endpoint-verification-630e5c4b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from paddock.finance](https://www.zero.xyz/host/paddock.finance/llms.txt)