x402 Base Tools – EIP-3009 Authorization Status Check

x402

x402 Base Tools – EIP-3009 Authorization Status Check is a paid API for AI agents from wt7tysfcmjm8fpzl.68r.lambda-web.us-east-1.on.aws, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-30).

Checks whether a specific EIP-3009 authorization nonce has been used and returns the authorizer's USDC balance on Base mainnet

Price / call$0.001

Seller volume →—

Success—

StatusUnknown

How this service works

Base mainnet data for agents, read live from the chain and paid per call in USDC: gas prices and costs, token prices from Uniswap and Aerodrome pools, balances, token info, transaction decoding, x402 payment checks, EIP-3009 authorization status, Basenames and address profiles. Lookups of things that do not exist are not charged.

Output

Returns a JSON object with 'used' (boolean indicating whether the authorization nonce has already been consumed) and 'usdc_balance' (string representing the authorizer's current USDC balance on Base, e.g. '2.89'). If the authorization or wallet does not exist, the call is not charged.

Example use cases

Prevent double-spend before payment relay

“Before I relay this signed USDC authorization, check if nonce 0x4f8e2a1b3c7d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f has already been used for wallet 0x1234567890abcdef1234567890abcdef12345678 on Base.”

Verify x402 payment authorization is still valid

“An agent just submitted an x402 payment request — can you verify that authorization nonce 0xaabbccddeeff00112233445566778899aabbccddeeff00112233445566778899aa for authorizer 0xDeAdBeEf0000000000000000000000000000dEaD hasn't been spent yet and they have enough USDC?”

Audit wallet USDC balance and nonce state

“I need to audit this wallet — check if nonce 0x0011223344556677889900aabbccddeeff0011223344556677889900aabbccdd is still unused and what USDC balance wallet 0x9999888877776666555544443333222211110000 currently holds on Base mainnet.”

Technical details

Endpoint

GEThttps://wt7tysfcmjm8fpzl.68r.lambda-web.us-east-1.on.aws/v1/authorization?utm_source=zero.xyz

When to prefer

Use this endpoint when you need to verify EIP-3009 USDC authorization status on Base mainnet before relaying a signed meta-transaction, or when you need to check a wallet's live USDC balance alongside nonce validity. Prefer this over generic RPC calls when you want pay-per-use pricing with no infrastructure setup, and when you need both nonce status and balance in a single call. Ideal for x402-enabled agent payment workflows on Base.

Side effects

Invalid nonce format (not 0x + 64 hex digits) returns an error
Invalid authorizer address format returns an error
RPC or chain read failure may return a 5xx error
Non-existent nonce/authorizer returns result without charge but may return null/default values

Input

Schema · Request body

Field	Type	Description
inputrequired	object
output	object

Output

Schema · Response

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

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