# DevX Agent Tools – On-Chain Payment Verification

> DevX Agent Tools – On-Chain Payment Verification is a paid API for AI agents from devx-x402-tools.nextill-pos.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-29).

Verifies that a specific blockchain transaction hash represents a valid USDC payment, returning confirmation count, transfer amounts, recipient, and whether a minimum threshold was met.

## Facts

- Endpoint: GET https://devx-x402-tools.nextill-pos.workers.dev/v1/payment/verify?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/devx-agent-tools-on-chain-payment-verification-dd65fd93
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HZweVWDkT0j00WbxOEvSI

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 devx-agent-tools-on-chain-payment-verification-dd65fd93
```

Example prompt: Can you verify that transaction 0xabc123...def on Base actually sent at least 5 USDC to 0xRecipientAddress...?

## When to prefer this

Choose this endpoint when you need to programmatically confirm that a specific on-chain USDC transaction actually occurred and met a payment threshold — especially useful for x402 pay-per-call workflows, digital commerce, or any agentic system that must gate actions on verified payment. Prefer it over manual block explorer checks or heavier indexing solutions when you need a lightweight, pay-per-use verification call with no API key setup.

## Known failure modes

- Transaction hash not yet indexed — returns found: false
- Invalid tx hash format — input rejected, no charge
- Network/chain not supported or unavailable — upstream failure, no charge
- Transaction found but no USDC transfers present — returns empty usdc_transfers array
- Minimum USDC not met — returns meets_min_usdc: false with actual amounts

## How this service works

Pay-per-call utilities for AI agents, no API key or signup: read any web page as clean Markdown ($0.002), link/SEO metadata ($0.001), domain DNS + SPF/DMARC email-security audit ($0.003), ERC-20 token safety pre-check ($0.005), crypto address validation, on-chain payment verification, EIP-681/BIP21/Solana Pay payment requests with QR, multichain USDC balances ($0.01). x402 v2, USDC on Base. Invalid input / upstream failure is never charged.

## Output

Returns a JSON object with: whether the transaction was found, its status (success/pending/failed), number of on-chain confirmations, a list of all USDC transfers (from/to/amount), the total USDC received by the specified recipient, and a boolean indicating whether the minimum USDC threshold was met.

## 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": {
      "to": {
       "type": "string"
      },
      "tx": {
       "type": "string"
      },
      "chain": {
       "type": "string"
      },
      "min_usdc": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": "base",
  "found": true,
  "status": "success",
  "confirmations": 12,
  "meets_min_usdc": true,
  "usdc_transfers": [
   {
    "to": "0x...",
    "from": "0x...",
    "token": "USDC",
    "amount": 5
   }
  ],
  "usdc_received_by_recipient": 5
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/devx-agent-tools-on-chain-payment-verification-dd65fd93/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from devx-x402-tools.nextill-pos.workers.dev](https://www.zero.xyz/host/devx-x402-tools.nextill-pos.workers.dev/llms.txt)