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ERC-20 Token Allowance Lookup (Optimism)
x402
ERC-20 Token Allowance Lookup (Optimism) 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).
Returns the ERC-20 token allowance granted by a token holder to a spender on the Optimism network
Price / call$0.002
Success—
StatusUnknown
How this service works
ERC-20 Allowance (optimism). Optimism ERC-20 allowance: how much a spender may move from an owner, human-readable, with an unlimited-approval flag.
Output
Returns the numeric allowance amount (in the token's base units) that a spender address is permitted to transfer on behalf of the owner address for the specified ERC-20 token contract on the Optimism network. Typically includes the raw allowance value as a big integer.
Example use cases
Verify DeFi protocol spending approval
“On Optimism, how many USDC tokens has my wallet 0xAbc...123 approved the Uniswap router 0xDef...456 to spend? The USDC contract is 0x7F5c764cBc14f9669B88837ca1490cCa17c31607.”
Audit token allowances before revoking
“I want to audit my token approvals — can you check the allowance for token contract 0x4200...0042 on Optimism where my wallet 0xOwner...789 is the holder and the suspected stale contract 0xOld...999 is the spender?”
Monitor smart contract approval limits
“Before triggering a swap, check whether the spender contract 0xRouter...321 has enough allowance to move tokens from 0xUser...654 on Optimism — the token is at contract address 0xToken...111.”
Technical details
Endpoint
GEThttps://saylorinnovations.com/api/evm/optimism/allowance/:address/:address2/:address3?utm_source=zero.xyzWhen to prefer
Use this endpoint when you specifically need to query ERC-20 token allowances on the Optimism L2 network. Prefer this over generic RPC calls when you need a simple, pay-per-call REST API without managing your own Optimism node or RPC credentials. Ideal for agents that need to verify DeFi approval states, audit token permissions, or gate actions on whether a contract has sufficient spending approval on Optimism.
Side effects
- Invalid or malformed Ethereum address returns an error or zero allowance
- Contract address is not a valid ERC-20 token contract — call may fail or return unexpected data
- Network connectivity issues to Optimism RPC nodes may cause timeouts
- Allowance is zero if the owner has never approved the spender — not an error, but a valid zero result
- Rate limiting or payment failure may block the request
Tags
x402
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