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Web3 Tools – EVM Calldata Splitter
x402
Web3 Tools – EVM Calldata Splitter is a paid API for AI agents from web3-tools.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-21).
Splits raw EVM calldata into its 4-byte function selector and 32-byte argument words, identifies known ERC-20/ERC-721 function signatures, and flags embedded Ethereum addresses.
Price / call$0.02
Success—
StatusUnknown
How this service works
Split EVM calldata into its 4-byte selector and 32-byte words, naming common ERC-20/721 calls and spotting addresses.
Output
Returns the 4-byte function selector, a human-readable known signature if recognized (e.g. 'transfer(address,uint256)' for ERC-20), an array of 32-byte argument words each annotated with its index, hex value, decoded uint256, and whether it looks like an Ethereum address, plus total byte counts, trailing byte count, an unlimited-approval flag, a summary verdict, and any applicable disclaimers.
Example use cases
Auditing a suspicious transaction
“I've got the input data from a transaction I'm suspicious about — can you split this calldata and tell me what function it's invoking and whether there are any addresses in the arguments? Here it is: 0x23b872dd000000000000000000000000ab5801a7d398351b8be11c439e05c5b3259aec9b000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa960450000000000000000000000000000000000000000000000000de0b6b3a7640000”
Detecting unlimited token approvals
“Before I sign this transaction, can you parse its calldata and check if it looks like an unlimited token approval? The hex is 0x095ea7b3000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25effffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff”
Debugging a failed contract call
“My contract call failed and I need to understand what was actually sent — can you break down this calldata into its selector and 32-byte words so I can see what arguments were encoded? Data: 0x70a08231000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045”
Technical details
Endpoint
GEThttps://web3-tools.x402tookit.com/calldata-split?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically decode raw EVM transaction input data without a full ABI — especially when you want automatic identification of common ERC-20/ERC-721 calls, embedded address detection, and unlimited-approval flagging in a single lightweight call. Prefer it over a full ABI decoder when you don't have the ABI or just need quick structural insight into what a transaction is doing.
Side effects
- Invalid or non-hex input returns an error
- Calldata shorter than 4 bytes cannot yield a selector
- Unknown selectors return null for knownSignature
- Truncated word list when calldata is very long (wordsTruncated: true)
- Missing required 'data' query parameter returns a validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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