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EVM Calldata Decoder
x402
EVM Calldata Decoder is a paid API for AI agents from apiacre.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).
Decodes EVM transaction calldata into human-readable form using a supplied function signature.
Price / call$0.001
Success—
StatusUnknown
How this service works
Resolve 29 common ERC-20, ERC-165, ERC-721, ERC-1155, ERC-2612, and ERC-3009 selectors without a network lookup, or strictly decode arbitrary Ethereum or EVM calldata using a supplied Solidity signature.
Output
Returns the decoded function name along with each parameter's name, type, and decoded value extracted from the supplied calldata hex string using the provided function signature.
Example use cases
Debug failing smart contract transaction
“I have a failed Ethereum transaction and I want to know exactly what parameters were passed. The calldata is 0x23b872dd000000000000000000000000abc...000000000000000000000000000000000000000000000000016345785d8a0000 and the function signature is transferFrom(address,address,uint256). Can you decode it?”
Audit on-chain governance vote calldata
“Can you decode this calldata from a DAO governance proposal so I can see what function was called and with what arguments? The hex is 0x7d5e81e2... and the signature is propose(address[],uint256[],bytes[],string).”
Monitor and interpret contract interactions
“I'm watching transactions to a DeFi protocol and I need to understand what swap parameters were used. Decode this calldata 0x38ed1739...000000 using the function signature swapExactTokensForTokens(uint256,uint256,address[],address,uint256).”
Technical details
Endpoint
POSThttps://apiacre.com/v1/crypto/calldata-decodeWhen to prefer
Choose this endpoint when you have raw EVM calldata hex and a known function signature and need to extract human-readable parameter values without setting up a local ABI decoder or Web3 library. Ideal for agents inspecting on-chain transactions, auditing contract calls, or building blockchain analytics pipelines where decoding is a single step in a larger workflow.
Side effects
- Invalid or malformed calldata hex returns a parsing error
- Mismatched function signature causes decoding failure or garbage output
- Missing or incomplete function signature returns an error
- Calldata too short for the specified parameter types causes a decode error
- Unsupported ABI types may not decode correctly
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| calldata | string | |
| input_mode | string | |
| function_signature | — |
Output
Schema · Response
{
"type": "json",
"example": {
"data": {
"types": [
"address",
"uint256"
],
"values": [
"0x1111111111111111111111111111111111111111",
42
],
"encoding": {
"canonical": true,
"argumentBytes": 64,
"calldataBytes": 68,
"calldataSha256": "f77b5da6ef3efa41f5084d653dc4a135a3978d541db97ce13225bd442b025198",
"argumentsSha256": "d3458da251349437abe3549042a49868dc5528422a63bb815f3e0b46725052c9"
},
"function": "transfer",
"selector": "0xa9059cbb",
"warnings": [
"Selector resolution is limited to 29 published standard signatures; four-byte..."
],
"arguments": [
{
"type": "address",
"index": 0,
"value": "0x1111111111111111111111111111111111111111"
}
],
"inputMode": "selector_and_arguments",
"signature": "transfer(address,uint256)",
"resolution": {
"method": "built_in_standard",
"candidates": [
"transfer(address,uint256)"
],
"candidateCount": 1,
"matchedStandards": [
"ERC-20"
],
"signatureProvided": false
},
"selectorPresent": true,
"signatureSource": "built_in_standard",
"canonicalSignature": "transfer(address,uint256)"
},
"meta": {
"cached": false,
"sources": [],
"warnings": [],
"duration_ms": 42,
"next_actions": []
},
"service": "crypto.calldata-decode",
"version": "1",
"request_id": "018f1f54-7f38-7ba2-8dc3-5f90272d9f1a"
}
}Tags
x402
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