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Lumen EVM Calldata Decoder
x402
Lumen EVM Calldata Decoder is a paid API for AI agents from lumenworks-x402-decoder.onrender.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).
Decodes raw EVM calldata into function selector, matching signatures from built-in and openchain/4byte databases, and ABI-decoded arguments for each candidate signature
Price / call$0.002
Success—
StatusUnknown
How this service works
Use when you hold raw EVM calldata and need to know what function it calls: returns selector, matching signatures (built-in + openchain/4byte) and ABI-decoded args for each candidate; unknown selecto…
Output
Returns the 4-byte function selector, the number of matching signatures found, the best-match source (built-in or openchain/4byte), the matched function signature string (e.g. 'transfer(address,uint256)'), and an array of candidate signatures each with their ABI-decoded argument values
Example use cases
Auditing unknown transaction input data
“I have this raw calldata from a pending Ethereum transaction: 0x23b872dd000000000000000000000000abc...123. Can you decode it and tell me what function it's calling and what the arguments are?”
Identifying smart contract method from mempool
“I grabbed this hex calldata from the mempool: 0x095ea7b3000000000000000000000000... — what EVM function is being called and what are the decoded parameters?”
Debugging a failed contract call
“My smart contract call failed and I only have the raw input data: 0x70a08231000000000000000000000000de0b295669a9fd93d5f28d9ec85e40f4cb697bae. Can you decode the calldata, figure out the function selector, and show me the ABI-decoded arguments?”
Technical details
Endpoint
POSThttps://lumenworks-x402-decoder.onrender.com/v1/calldata/decode?utm_source=zero.xyzWhen to prefer
Use this endpoint when you have raw hex calldata from an EVM transaction and need to identify the function being called and decode its arguments without having the ABI on hand. Ideal for security review, transaction auditing, mempool analysis, or debugging failed calls. Prefer this over manual ABI lookups when the contract ABI is unavailable and the selector needs to be resolved from public signature databases.
Side effects
- Unknown selector: calldata selector not found in built-in or openchain/4byte databases — returns selector with empty candidates
- Malformed calldata: non-hex or truncated input causes a parse error response
- Ambiguous signatures: multiple candidates returned when selector maps to more than one signature — agent must choose
- Network timeout: openchain/4byte external lookup fails, may return partial results from built-in database only
Output
Schema · Response
{
"type": "json",
"example": {
"source": "openchain/4byte",
"decoded": {
"args": [
"0xee9790cB3960952F585379F831a89b4e00B4029A",
"1000000"
],
"signature": "transfer(address,uint256)"
},
"selector": "0xa9059cbb",
"candidates": [
{
"args": [
"0xee9790cB3960952F585379F831a89b4e00B4029A",
"1000000"
],
"signature": "transfer(address,uint256)"
}
],
"signaturesFound": 1
}
}Tags
x402
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