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Delx Commerce — EVM Transaction Selector Extractor
x402
Delx Commerce — EVM Transaction Selector Extractor is a paid API for AI agents from commerce.delx.ai, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-02).
Extracts the 4-byte ABI function selector and remaining calldata byte count from raw EVM transaction calldata hex.
Price / call$0.003
Success—
StatusUnknown
How this service works
Pay-per-result APIs for agents. No signup. Exact price. Verifiable delivery. USDC on Base + Solana via x402.
Output
Returns a JSON object with a validity boolean, a schema identifier string (e.g. 'delx/util-selector-extract/v1'), the extracted 4-byte function selector as a hex string (e.g. '0xa9059cbb'), and the count of remaining bytes after the selector in the calldata.
Example use cases
Identify ERC-20 transfer calls
“I have this raw calldata from an Ethereum transaction: 0xa9059cbb0000000000000000000000001234567890abcdef1234567890abcdef123456780000000000000000000000000000000000000000000000000de0b6b3a7640000 — can you extract the function selector and tell me how many parameter bytes are in it?”
Audit unknown smart contract invocation
“Someone sent a suspicious transaction to a smart contract and I have the raw calldata hex: 0x23b872dd000000000000000000000000abc — what function selector is being called and how many bytes of arguments does it carry?”
Decode calldata in blockchain agent pipeline
“As part of my transaction monitoring pipeline, decode the function selector from this calldata hex 0x095ea7b3000000000000000000000000router00000000000000000000000000000000ffff and confirm whether it's a valid ABI-encoded call.”
Technical details
Endpoint
POSThttps://commerce.delx.ai/api/v1/x402/selector-extract?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a lightweight, pay-per-use, no-signup way to programmatically extract and validate the ABI function selector from raw EVM transaction calldata. It is ideal for blockchain agents, transaction monitoring pipelines, and smart contract auditing tools that need to quickly identify which Solidity function a raw hex payload targets without spinning up a local EVM decoder. Prefer it over full node RPC calls or heavy decoding libraries when you only need the selector and byte count in a single fast API call.
Side effects
- Malformed or non-hex calldata string returns valid:false
- Calldata shorter than 4 bytes cannot yield a selector
- Missing 'calldata' field in request body causes validation error
- Payment failure via x402 protocol prevents execution
- Truncated calldata may return a selector but incorrect remaining_bytes count
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| calldata | string | Transaction calldata hex; first 4 bytes are the selector. |
Output
Schema · Response
{
"type": "json",
"example": {
"valid": true,
"schema": "delx/util-selector-extract/v1",
"selector": "0xa9059cbb",
"remaining_bytes": 32
}
}Tags
x402
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