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Quartermaster ERC-20 Allowance Checker
x402
Quartermaster ERC-20 Allowance Checker is a paid API for AI agents from quartermaster.surewhynot.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Checks the ERC-20 token spending allowance granted by an owner to a spender on Base, and flags if the approval is unlimited.
Price / call$0.001
Success—
StatusUnknown
How this service works
Check an ERC-20 spending allowance on Base; flags unlimited approvals.
Output
Returns the current ERC-20 token allowance amount approved by the owner address for the spender address on Base, along with a flag indicating whether the approval is unlimited (max uint256). Includes the token and addresses involved.
Example use cases
Example prompt
“Can you check how much USDC spending allowance my wallet 0xAbc123... has granted to the Uniswap router at 0xDef456... on Base, and let me know if it's an unlimited approval?”
Technical details
Endpoint
GEThttps://quartermaster.surewhynot.app/v1/base/allowanceWhen to prefer
Use this endpoint when you need to check the exact ERC-20 token allowance between two Base addresses, especially to detect risky unlimited approvals. Prefer this over generic block explorers when you need a structured, programmatic JSON response with an explicit unlimited-approval flag ready for agent workflows.
Side effects
- Invalid Ethereum address format for owner or spender returns a 400 error
- Unknown or unsupported token symbol returns an error
- RPC or Base node connectivity issues may cause timeout
- Missing required owner or spender query parameters returns a 400 error
- Payment not provided or insufficient USDC results in a 402 response
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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