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Solidity Function Selector Calculator
x402
Solidity Function Selector Calculator is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).
Computes the 4-byte ABI function selector from a Solidity function signature string
Price / call$0.001
Success—
StatusUnknown
How this service works
Function selector from a Solidity signature — Genesis402 / UnyKorn Operator Network
Output
Returns a JSON object confirming success, the computed 4-byte ABI function selector hex string derived from the provided Solidity signature, along with a payment receipt including transaction hash, amount in USD, and a unique receipt ID.
Example use cases
Debugging raw EVM calldata
“I'm looking at some raw transaction calldata and need to figure out which function was called — can you give me the selector for balanceOf(address) so I can compare it to the first 4 bytes?”
Building a smart contract interaction tool
“I'm writing a script to manually encode a function call to approve(address,uint256) — what's the 4-byte function selector I need to prepend to the ABI-encoded arguments?”
Verifying selector collision between functions
“I want to check the function selectors for transferFrom(address,address,uint256) and any potential collisions — can you compute the selector for that signature?”
Technical details
Endpoint
POSThttps://twin.unykorn.org/abi-function-selector?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a quick, paid, on-demand computation of the Solidity ABI function selector from a human-readable function signature, especially in agentic workflows that already use the x402 micropayment protocol. Prefer it when you want a verifiable receipt of the computation and are working within the UnyKorn/Genesis402 ecosystem alongside other blockchain utilities like calldata splitting or EVM chain lookups.
Side effects
- Invalid or malformed Solidity signature string causes an error response
- Missing required 'signature' field in the params object
- Network timeout or service unavailability returns a non-200 response
- Payment failure via x402 protocol prevents computation
- Signature with unsupported or non-standard types may produce unexpected results
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| params | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"type": "abi-function-selector",
"receipt": {
"tx_hash": "0x<64hex>",
"amount_usd": 0.001,
"receipt_id": "g402-<16hex>"
},
"generated_at": "<iso8601>"
}
}Tags
x402
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