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EVM Contract Bytecode Fetcher
x402
EVM Contract Bytecode Fetcher is a paid API for AI agents from chain.openverbs.com, paid per call via x402, $0.006/call, status unknown (last checked 2026-10-10).
Fetches the deployed runtime bytecode and Keccak-256 code hash of any EVM smart contract address across Ethereum, Base, Arbitrum, Optimism, and Polygon, with optional historical block support.
Price / call$0.006
Success—
StatusUnknown
How this service works
Fetch deployed EVM contract runtime bytecode and its Keccak-256 code hash to fingerprint or compare contracts, or feed a disassembler. Supports Ethereum, Base, Arbitrum, Optimism and Polygon, with optional historical block reads. Returns full hex code, byte size and isContract; an empty-code address returns 0x and a null hash. Key-free RPC with endpoint fallback; code capped at 256 KiB.
Output
Returns a JSON object containing the full hex-encoded runtime bytecode (capped at 256 KiB), the Keccak-256 hash of that code, the byte length, and a boolean isContract field. For non-contract (EOA) addresses, bytecode is '0x' and the hash is null.
Example use cases
Contract identity verification
“I need to verify that the contract at 0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984 on Ethereum is genuinely the Uniswap token — can you fetch its bytecode and code hash so I can compare it against the known deployment?”
Historical bytecode snapshot
“Fetch the runtime bytecode of the contract at 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D on Ethereum as it existed at block 15000000, so I can see if it was upgraded since then.”
Check if address is a contract
“Can you check whether the address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Ethereum is actually a deployed contract or just a regular wallet — fetch its code and tell me the byte size?”
Technical details
Endpoint
POSThttps://chain.openverbs.com/v1/bytecode?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to retrieve, fingerprint, or compare the deployed runtime bytecode of a smart contract on any of the five supported EVM chains (Ethereum, Base, Arbitrum, Optimism, Polygon). It is ideal for security audits, contract identity verification, detecting proxy upgrades at historical blocks, or feeding raw bytecode to a disassembler. It requires no API key and handles RPC fallback automatically. Prefer it over general block explorers when you need structured, machine-readable bytecode output rather than a human-facing UI.
Side effects
- Invalid address format (not a valid 0x-prefixed 40-hex-char address) returns a validation error
- Unsupported chain name returns an enum validation error
- Block number out of range or not yet mined returns an RPC error
- Address is an EOA — returns 0x bytecode and null hash (not an error, but isContract is false)
- Bytecode exceeds 256 KiB cap — response is truncated or rejected
- RPC node unavailability on the selected chain triggers endpoint fallback; if all fail, returns a service error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| block | — | Non-negative safe integer, decimal/hex block number, or latest/earliest/pending/safe/finalized. Default latest. |
| chain | string | EVM chain to query. One of: ethereum, base, arbitrum, optimism, polygon. Default "ethereum". |
| address | string | Address whose deployed code to read. |
Tags
x402
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