# Ontario Protocol Base Transaction Checker

> Ontario Protocol Base Transaction Checker is a paid API for AI agents from ontarioprotocol.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-30).

Looks up a Base mainnet transaction by hash, decodes ERC-20 transfers and EIP-3009 authorizations, and optionally verifies that a specific payTo address and amount were satisfied — ideal for confirming x402 payment settlement.

## Facts

- Endpoint: GET https://ontarioprotocol.com/api/x402/base/tx-check?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ontario-protocol-base-transaction-checker-e241cd62
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ApIwbRLS83B1zVqR-F6Ns

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 ontario-protocol-base-transaction-checker-e241cd62
```

Example prompt: Can you check whether this Base transaction settled and confirm that 0.5 USDC actually reached 0xa2d72aBF2C5e939fdDCA4156B74dE482e03CA3ec? The tx hash is 0xfe14a1712c65c815f1f056cb6b2fbe0f72b2b44eee0990bab5ece2914d7a0883 and the expected amount is 500000 atomic units.

## When to prefer this

Use this endpoint when you need to confirm settlement of a Base mainnet transaction, especially for x402 payment verification where you must validate that USDC reached a specific recipient address at a specific amount. It is the right choice when you need decoded ERC-20 transfers and EIP-3009 authorization data in a single call, without needing a full blockchain explorer or holding an API key. Prefer it over generic RPC calls when you want match flags for payTo/amount validation built in.

## Known failure modes

- Transaction hash not found on Base mainnet — no charge, response indicates not found
- Invalid hash format (not 0x + 64 hex chars) — rejected before payment
- Network connectivity issues to Base RPC — may return error
- Transaction too recent and not yet indexed — may return not found
- More than 100 transfers in the transaction — only first 100 listed, transfers_total gives full count

## How this service works

Did this Base payment settle? Status, block, timestamp and confirmations for one transaction hash, with its ERC-20 Transfers decoded (token, from, to, amount; up to 100 listed, transfers_total gives the full count) and any EIP-3009 authorization used, plus match flags for an optional expected payTo and amount, so an x402 PAYMENT-RESPONSE can be checked. Required: hash. $0.002 USDC on Base. Transaction not found, no charge. No account, no API key. Base mainnet only. By Ontario Protocol.

## Output

Returns transaction status (success/failed/pending), block number, timestamp, confirmations count, decoded ERC-20 transfers (up to 100, with token address, symbol, decimals, from, to, raw and formatted amounts), EIP-3009 authorization details, a USDC payment summary, gas used, effective gas price, and — when expected_to and expected_amount are provided — boolean match flags indicating whether those conditions were met.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input",
  "output"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "queryParams"
   ],
   "properties": {
    "queryParams": {
     "type": "object",
     "required": [
      "hash"
     ],
     "properties": {
      "hash": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{64}$",
       "description": "Base mainnet transaction hash."
      },
      "expected_to": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "Optional payTo address the USDC transfer should reach."
      },
      "expected_amount": {
       "type": "string",
       "pattern": "^[0-9]{1,78}$",
       "description": "Optional USDC amount in atomic units, for example 500000 for 0.5 USDC."
      }
     },
     "additionalProperties": false
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "example"
   ],
   "properties": {
    "example": {
     "type": "object",
     "additionalProperties": true
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "example": {
  "to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "from": "0x2A89407a98A0732b7fD578c4E156B7166540EB5A",
  "hash": "0xfe14a1712c65c815f1f056cb6b2fbe0f72b2b44eee0990bab5ece2914d7a0883",
  "block": 51838957,
  "schema": "ontario.base_tx_check.v1",
  "source": "Base RPC",
  "status": "success",
  "network": "eip155:8453",
  "read_at": "2026-10-25T00:46:05Z",
  "expected": {
   "to": "0xa2d72aBF2C5e939fdDCA4156B74dE482e03CA3ec",
   "rule": "Any USDC Transfer in the transaction; with expected_to set, the amount must be on a transfer to it.",
   "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "to_matches": true,
   "amount_atomic": "500000",
   "amount_matches": true
  },
  "gas_used": 86302,
  "timestamp": "2026-09-27T00:01:01Z",
  "transfers": [
   {
    "to": "0xa2d72aBF2C5e939fdDCA4156B74dE482e03CA3ec",
    "raw": "500000",
    "from": "0xc9c7b38C0942914fC8EA12063BC92dcd3b581670",
    "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "symbol": "USDC",
    "decimals": 6,
    "formatted": "0.5"
   }
  ],
  "block_hash": "0xa6d26e6d5666d11350491e89b07659b8887804b3d6d7fac532c4da1ec4a4fceb",
  "usdc_payment": {
   "payer": "0xc9c7b38C0942914fC8EA12063BC92dcd3b581670",
   "recipient": "0xa2d72aBF2C5e939fdDCA4156B74dE482e03CA3ec",
   "amount_usdc": "0.5",
   "amount_atomic": "500000",
   "eip3009_authorization_observed": true
  },
  "confirmations": 1210953,
  "transfers_total": 1,
  "authorizations_used": [
   {
    "nonce": "0x366fed83f5c2c8d619f993a8d33c75765208dde91a214676944640d98d040178",
    "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "authorizer": "0xc9c7b38C0942914fC8EA12063BC92dcd3b581670"
   }
  ],
  "effective_gas_price_wei": "6857500"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ontario-protocol-base-transaction-checker-e241cd62/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ontarioprotocol.com](https://www.zero.xyz/host/ontarioprotocol.com/llms.txt)