# x402 Base Tools – USDC Authorization Nonce Status & Balance

> x402 Base Tools – USDC Authorization Nonce Status & Balance is a paid API for AI agents from base.kagurazaka.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-29).

Checks whether a USDC transferWithAuthorization nonce has been used on Base and returns the authorizer's current USDC balance, letting x402 payment flows confirm settlement.

## Facts

- Endpoint: GET https://base.kagurazaka.dev/v1/authorization?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-base-tools-usdc-authorization-nonce-status-balance-27593877
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PqAfXFsddjtD5IAKThsR8

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 x402-base-tools-usdc-authorization-nonce-status-balance-27593877
```

Example prompt: Has the USDC authorization nonce 0xabc123...def456 already been used on Base for wallet 0x1234...5678, and what's their current USDC balance?

## When to prefer this

Use this endpoint when building or verifying x402 payment flows on Base and you need to determine in one call whether a specific USDC transferWithAuthorization nonce has been consumed and check the payer's current USDC balance. Prefer it over general blockchain explorers when you need fast, structured JSON output for programmatic settlement confirmation without parsing raw transaction logs.

## Known failure modes

- Invalid or malformed nonce format (not 0x + 64 hex digits) returns an error
- Invalid or non-checksummed authorizer address returns an error
- Missing required query parameters returns a 400-level error
- Network or RPC issues reading Base chain state may cause transient failures
- Nonce or balance data may lag slightly behind the latest block

## How this service works

Whether a USDC transferWithAuthorization nonce of an authorizer has already been used on Base, which is how an x402 buyer tells a settled payment from one that never landed, plus the authorizer's USDC balance.

## Output

A JSON object with a boolean `used` field indicating whether the nonce has been consumed on-chain, and a `usdc_balance` string showing the authorizer's current USDC balance (e.g. {"used": false, "usdc_balance": "2.89"}).

## 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": [
      "authorizer",
      "nonce"
     ],
     "properties": {
      "nonce": {
       "type": "string",
       "description": "the authorization nonce (0x + 64 hex digits)"
      },
      "authorizer": {
       "type": "string",
       "description": "the paying wallet (0x...)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "used": {},
      "usdc_balance": {}
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "used": false,
  "usdc_balance": "2.89"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-base-tools-usdc-authorization-nonce-status-balance-27593877/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from base.kagurazaka.dev](https://www.zero.xyz/host/base.kagurazaka.dev/llms.txt)