# RelayHop Payment Verifier (Base Chain)

> RelayHop Payment Verifier (Base Chain) is a paid API for AI agents from payment-verifier-cdp.relayhop.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Verifies on-chain transactions on the Base network, returning verified status, amount, sender, recipient, block number, and confirmation signals for a given transaction hash.

## Facts

- Endpoint: GET https://payment-verifier-cdp.relayhop.workers.dev/v1/check
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/payment-verifier-cdp-relayhop-workers-dev-058d74f6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vQJvPl9w58jXQSgzIT1GR

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 payment-verifier-cdp-relayhop-workers-dev-058d74f6
```

Example prompt: Can you verify whether this Base transaction actually went through and tell me who sent it, who received it, and how much? The tx hash is 0x4f3c2a1b8e7d6f5a9c0b2e4d1f8a3c7e6b5d4f2a1e9c8b7a6d5f4e3c2b1a0f9e.

## When to prefer this

Use this endpoint when you need real-time on-chain confirmation of a specific Base network transaction, especially to programmatically verify payments or smart contract interactions using a transaction hash. Ideal for post-payment confirmation flows, receipt validation, or fraud checks in Base/USDC-based payment pipelines.

## Known failure modes

- Invalid or malformed transaction hash returns an error or unverified status
- Transaction not yet confirmed may return verified: false
- Transaction on a chain other than Base will not resolve
- Network RPC errors or timeouts may cause incomplete responses
- Missing required 'tx' query parameter returns a validation error

## How this service works

Real-time on-chain payment verification and check via Base RPC. Returns structured signals: verified status, amount, sender, recipient, transaction confirmation, block number. Pay $0.005 USDC per check. Covers payment, transaction, address, contract, score, signals.

## Output

Returns a JSON object with: verified (boolean), amount (string), sender (address), recipient (address), asset (e.g. USDC), chain (e.g. base), tx_hash, block_number (integer), confirmed_at (timestamp), and a signals array of descriptive tags about the transaction.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "tx": "0x4f3c2a1b8e7d6f5a9c0b2e4d1f8a3c7e6b5d4f2a1e9c8b7a6d5f4e3c2b1a0f9e"
  }
 }
}
```

## 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",
     "required": [
      "tx"
     ],
     "properties": {
      "tx": {
       "type": "string",
       "description": "Transaction hash (0x + 64 hex chars)"
      }
     }
    }
   }
  },
  "output": {
   "type": "object",
   "properties": {
    "asset": {
     "type": "string"
    },
    "chain": {
     "type": "string"
    },
    "amount": {
     "type": "string"
    },
    "sender": {
     "type": "string"
    },
    "signals": {
     "type": "array",
     "items": {
      "type": "string"
     }
    },
    "tx_hash": {
     "type": "string"
    },
    "verified": {
     "type": "boolean"
    },
    "recipient": {
     "type": "string"
    },
    "block_number": {
     "type": "number"
    },
    "confirmed_at": {
     "type": "number"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/payment-verifier-cdp-relayhop-workers-dev-058d74f6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payment-verifier-cdp.relayhop.workers.dev](https://www.zero.xyz/host/payment-verifier-cdp.relayhop.workers.dev/llms.txt)