# Proofwork Base USDC Balance Lookup

> Proofwork Base USDC Balance Lookup is a paid API for AI agents from proofwork-the402-webhook.phase-voice.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Returns the current USDC token balance for a given Ethereum address on Base Mainnet, with a Basescan evidence link, payable per-request via x402.

## Facts

- Endpoint: GET https://proofwork-the402-webhook.phase-voice.workers.dev/v1/base-usdc-balance
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/proofwork-base-usdc-balance-lookup-1da60865
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xtHQed_IjOPCBFNW-wFhO

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 proofwork-base-usdc-balance-lookup-1da60865
```

Example prompt: What's the current USDC balance on Base Mainnet for the wallet address 0x1212121212121212121212121212121212121212? I want the on-chain evidence link too.

## When to prefer this

Choose this endpoint when you need a verifiable, on-chain USDC balance report for a specific Base Mainnet address with an evidence link to Basescan. Ideal for agents that need lightweight, pay-per-call balance lookups without setting up a full RPC node or blockchain SDK. Prefer over generic blockchain explorers when you want a structured JSON response with an embedded evidence trail, especially in automated workflows where per-request micropayment via x402 is acceptable.

## Known failure modes

- Invalid or malformed Ethereum address (not matching 0x + 40 hex chars) returns a validation error
- Address with no USDC holdings returns a balance of '0' (not an error)
- Network connectivity issues to Base Mainnet may return a timeout or upstream error
- x402 payment failure results in a 402 response before any data is returned

## How this service works

Small non-cyber evidence and data APIs payable per request with x402 on Base.

## Output

A JSON object containing the report type ('base_usdc_balance'), the queried wallet address, the USDC balance as a string, the network name ('Base Mainnet'), and an array of Basescan evidence URLs linking to the address for independent verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "queryParams"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "report": "base_usdc_balance",
  "account": {
   "address": "0x1212121212121212121212121212121212121212",
   "balance_usdc": "0"
  },
  "network": "Base Mainnet",
  "evidence": [
   "https://basescan.org/address/0x1212121212121212121212121212121212121212"
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/proofwork-base-usdc-balance-lookup-1da60865/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from proofwork-the402-webhook.phase-voice.workers.dev](https://www.zero.xyz/host/proofwork-the402-webhook.phase-voice.workers.dev/llms.txt)