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HALOWERK kettenwerk Contract Verification Checker
x402
HALOWERK kettenwerk Contract Verification Checker is a paid API for AI agents from kette.halowerk.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-13).
Checks whether a smart contract (and its implementation, if it's a proxy) is source-verified on Ethereum, Base, Arbitrum, Optimism, Polygon, or BNB Smart Chain
Price / call$0.004
Success—
StatusUnknown
How this service works
Checks one address on Ethereum, Base, Arbitrum, Optimism, Polygon or BNB Smart Chain against the open verification registry and against the chain itself. For a proxy the answer is deliberately split in two: whether the proxy is verified says almost nothing, whether the implementation it currently points to is verified is the real question, and both are reported separately with the implementation address read from the EIP-1967 storage slot, the EIP-1167 clone pattern or an implementation() call —
Output
Returns two separate verification statuses: one for the contract address itself (is it verified in the open registry?), and one for the implementation it currently points to if the contract is a proxy — resolved via EIP-1967 storage slot, EIP-1167 clone detection, or an implementation() call. The implementation address is also returned. This split answer allows the caller to understand whether the meaningful code layer (the implementation) is inspectable, not just the proxy shell.
Example use cases
DeFi contract trust check before interaction
“Before I sign this transaction, can you check if the contract at 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D on Ethereum is source-verified? And if it's a proxy, is the underlying implementation verified too?”
New token contract due diligence
“I'm looking at this token contract on BSC — 0x8AC76a51cc950d9822D68b83fE1Ad97B32Cd580d — can you tell me if it's source-verified on the open registry and whether there's a proxy pointing to an unverified implementation?”
Arbitrum protocol security audit assist
“We're auditing a protocol on Arbitrum. Check contract 0x912CE59144191C1204E64559FE8253a0e49E6548 — is it verified, and if it's a proxy, what's the implementation address and is that verified?”
Technical details
Endpoint
POSThttps://kette.halowerk.com/contract/verification?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to determine whether a smart contract's source code is publicly verified before interacting with it, auditing it, or presenting it to a user. It is especially valuable for proxy contracts, where the surface-level proxy may be verified while the actual logic implementation is not — a distinction most generic block explorer lookups miss. Prefer this over manual Etherscan lookups when operating across multiple EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon, BSC) and when proxy-awareness (EIP-1967, EIP-1167, implementation() call) is required.
Side effects
- Invalid or non-checksummed address format returns a validation error
- Unsupported chain enum value returns an error
- Contract does not exist at the given address on the specified chain
- Proxy pattern not recognized — implementation address cannot be resolved
- Block explorer or RPC temporarily unavailable — verification registry unreachable
- Network timeout when reading EIP-1967 storage slot or calling implementation()
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| chain | string | Chain the contract lives on. |
| address | string | Contract address. |
Tags
x402
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