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ERC-20 Token Allowance Lookup on Base (Saylor Innovations)
x402
ERC-20 Token Allowance Lookup on Base (Saylor Innovations) is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-30).
Retrieves the current ERC-20 token spending allowance granted by a token owner to a spender on the Base blockchain
Price / call$0.002
Success—
StatusUnknown
How this service works
ERC-20 Allowance (base). Base ERC-20 allowance: how much a spender may move from an owner, human-readable, with an unlimited-approval flag.
Output
Returns the current allowance (in token base units/wei) that the token owner has approved the spender to transfer on their behalf for the specified ERC-20 token contract on the Base blockchain. Typically includes the numeric allowance value reflecting the on-chain state at query time.
Example use cases
Pre-swap allowance check for DeFi
“Before I do a token swap on a Base DEX, can you check how many USDC tokens the wallet 0xABC123 has approved the Uniswap router at 0xDEF456 to spend — the USDC contract is at 0xTokenXYZ?”
Audit wallet approvals for security
“I want to audit my wallet's risk exposure — can you look up how much of the token at 0xTokenContract the spender contract 0xSpenderContract is allowed to take from my wallet 0xMyWallet on Base?”
Verify allowance before batch transfer
“We're about to trigger a batch transfer from 0xOwnerWallet using the operator contract 0xOperatorAddress for the token 0xERC20Token on Base — can you confirm the current approved allowance is sufficient?”
Technical details
Endpoint
GEThttps://saylorinnovations.com/api/evm/base/allowance/:address/:address2/:address3?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a quick, pay-per-call lookup of an ERC-20 token allowance on the Base network without running your own Base RPC node or blockchain indexer. It is ideal for AI agents or automation workflows that need real-time on-chain approval data before executing DeFi operations, auditing wallet permissions, or validating spending limits. Prefer this over general Ethereum RPC endpoints when your target chain is specifically Base and you want a simple REST interface instead of raw JSON-RPC calls.
Side effects
- Invalid or malformed Ethereum address for any of the three address parameters returns an error
- Token contract address does not implement ERC-20 allowance, causing a contract call failure
- Address not found or no allowance set (returns zero, which may be misinterpreted as an error)
- Base RPC node unavailability causing timeout or service error
- Rate limiting if the endpoint is called excessively within a short window
Tags
x402
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