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EVM Bytecode Size Checker
x402
EVM Bytecode Size Checker is a paid API for AI agents from api.x402node.dev, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-15).
Returns the bytecode size of an address on up to 7 EVM chains, distinguishing EOAs (size=0) from smart contracts (size>0).
Price / call$0.004
Success—
StatusUnknown
How this service works
Bytecode size of an address across 7 EVM chains - zero means a regular wallet (EOA), non-zero means a contract with the byte count indicating complexity - a fast primitive for agents to distinguish wallets from contracts before interacting. code size, is contract, bytecode size, eoa or contract, contract bytecode, account code
Output
Returns the bytecode size (in bytes) of the given address on each supported EVM chain. A size of 0 means it is a regular wallet (EOA); any non-zero value means it is a deployed smart contract, with the byte count indicating relative complexity. Results are returned per chain.
Example use cases
Example prompt
“Is 0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984 a wallet or a smart contract? Check across all available EVM chains and tell me the bytecode size.”
Technical details
Endpoint
GEThttps://api.x402node.dev/chain/code-sizeWhen to prefer
Use this endpoint when you need to quickly determine whether an Ethereum-style address is a wallet (EOA) or a deployed smart contract before interacting with it programmatically — especially when operating across multiple EVM chains at once. Prefer this over full ABI fetching or Etherscan lookups when you only need a fast binary wallet-vs-contract check plus a rough complexity signal from byte count.
Side effects
- Invalid or malformed Ethereum address returns an error response
- Address not found or chain unavailable may return null or zero for that chain
- Unsupported chain identifier returns an error
- Network timeout on a specific chain may yield partial results
Input
{
"address": "0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984"
}Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Output
{
"note": "Bytecode size of an address. 0 = EOA (wallet); >0 = contract. Larger size often = more complex contract. Agents use to know if an address is a contract before interacting.",
"_hint": "x402 paid endpoints for AI agents — x402node.dev (utilities) · cn402.com (Chinese culture)",
"chain": "base",
"source": "rpc",
"address": "0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984",
"isContract": true,
"codeSizeBytes": 2109
}Tags
x402
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