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Base Token Approval Check
x402
Base Token Approval Check is a paid API for AI agents from automaton-tx-explainer.vercel.app, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-18).
Checks all ERC-20 token approvals (allowances) granted by a given Base mainnet wallet address, identifying unlimited and non-zero approvals
Price / call$0.005
Success—
StatusUnknown
How this service works
Check a Base wallet's ERC-20 approvals: allowances for 8 major tokens (USDC, WETH, USDbC, DAI...) to common spenders (Permit2, Uniswap Universal Router, Uniswap SwapRouter02, Aerodrome Router...); flags unlimited approvals.
Output
Returns the wallet owner address, total number of token-spender pairs checked, count of unlimited approvals, and a list of non-zero approvals each containing the token name, spender name, allowance amount, and a boolean indicating whether it is unlimited.
Example use cases
Wallet security audit before DeFi use
“I want to audit my Base wallet 0x1234567890abcdef1234567890abcdef12345678 — show me all the token approvals I've granted, especially any that are unlimited, so I can decide which ones to revoke.”
Checking Permit2 exposure on Base
“Does my Base address 0xDeAdBeEf1234567890abcdef1234567890abcdef have any unlimited Permit2 approvals? I want to know if I'm exposed before I move any funds.”
Onboarding compliance check for new wallet
“Before we onboard this user's Base wallet 0xAaBb1234567890abcdef1234567890abcdef1234, can you pull all their existing token approvals and tell me how many non-zero allowances they have outstanding?”
Technical details
Endpoint
GEThttps://automaton-tx-explainer.vercel.app/v1/base/approvals?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a quick, pay-per-call audit of ERC-20 token approvals on Base mainnet for a specific wallet address. It is particularly valuable for security reviews, pre-transaction risk checks, and DeFi onboarding flows where knowing which spenders have active allowances (especially unlimited ones) is critical. Prefer this over general blockchain explorers when you need structured, machine-readable approval data rather than a UI. Choose this over a full transaction explainer when the specific goal is allowance enumeration, not transaction decoding.
Side effects
- Invalid or malformed wallet address (must match ^0x[0-9a-fA-F]{40}$) returns a validation error
- Address with no approvals returns an empty nonZeroApprovals array
- Payment failure or missing x402 USDC payment header returns 402 Payment Required
- Rate limiting or downstream Base RPC unavailability may cause transient 5xx errors
- Address with very large approval history may increase latency
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"owner": "0x...",
"checkedPairs": 64,
"unlimitedCount": 1,
"nonZeroApprovals": [
{
"token": "USDC",
"spender": "Permit2",
"allowance": "unlimited",
"unlimited": true
}
]
}
}Tags
x402
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