# Northline ChainKit Payment Verify

> Northline ChainKit Payment Verify is a paid API for AI agents from northline-chainkit.northline-c86.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-31).

Verifies that a USDC payment transaction on Base or Arc blockchain was received by a specified address with optional amount and confirmation thresholds

## Facts

- Endpoint: GET https://northline-chainkit.northline-c86.workers.dev/v1/payment/verify?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/northline-chainkit-payment-verify-eeef0db1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ucf9pEny-eQpTzSIG_IDk

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 northline-chainkit-payment-verify-eeef0db1
```

Example prompt: Can you verify that transaction 0xabc123...def456 actually sent at least 0.01 USDC to my wallet 0xDEAD...BEEF on Base, and confirm it has at least 10 confirmations?

## When to prefer this

Use this endpoint when you need to programmatically confirm that a specific USDC transaction landed on the Base or Arc blockchain before delivering a product, granting access, or continuing a workflow. It is purpose-built for x402 pay-per-call patterns where each API invocation is gated behind a micropayment. Prefer it over generic blockchain explorers when you need structured machine-readable output, support for both Base and Arc networks, and configurable minimum amount and confirmation thresholds in a single call.

## Known failure modes

- Invalid transaction hash format returns schema validation error
- Transaction not found on specified chain returns verified:false with reasons
- Received amount below minAmount threshold returns verified:false
- Confirmation count below minConfirmations returns verified:false
- Incorrect 'to' address mismatch returns verified:false
- Network issues with Base or Arc RPC returns 5xx error
- Missing required 'tx' or 'to' query parameters returns 400 error

## How this service works

x402 pay-per-call onchain API (Base + Arc).

## Output

Returns a JSON object with a boolean 'verified' field, the 'receivedUsdc' amount as a string, the number of 'confirmations', and a 'reasons' array listing any failure conditions (e.g. insufficient amount, unconfirmed, wrong recipient).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "tx",
      "to"
     ],
     "properties": {
      "to": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$"
      },
      "tx": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{64}$"
      },
      "from": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$"
      },
      "chain": {
       "enum": [
        "base",
        "arc"
       ],
       "type": "string",
       "default": "base"
      },
      "minAmount": {
       "type": "string"
      },
      "minConfirmations": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "reasons": [],
  "verified": true,
  "receivedUsdc": "0.01",
  "confirmations": 120
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/northline-chainkit-payment-verify-eeef0db1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from northline-chainkit.northline-c86.workers.dev](https://www.zero.xyz/host/northline-chainkit.northline-c86.workers.dev/llms.txt)