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Solidity Function Selector Calculator
x402
Solidity Function Selector Calculator is a paid API for AI agents from agentresolver.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-18).
Computes the 4-byte ABI function selector and full keccak256 hash for a given Solidity function signature
Price / call$0.01
Success—
StatusUnknown
How this service works
Verify an x402 endpoint before paying: live payTo, USDC quote, network, asset, resource binding, TLS and endpoint safety for $0.001 on Base or Solana.
Output
Returns a JSON object containing the original function signature, the 4-byte hex ABI function selector (e.g. 0xa9059cbb), and the full 32-byte keccak256 hash of the signature string.
Example use cases
Decoding unknown contract calldata
“I'm seeing raw calldata starting with 0xa9059cbb on Etherscan — can you figure out which Solidity function signature produces that selector?”
Building an ABI encoder tool
“I need the 4-byte selector and full keccak256 hash for the function signature approve(address,uint256) so I can encode a raw transaction.”
Auditing smart contract dispatch logic
“Can you compute the function selectors for transferFrom(address,address,uint256) and safeTransferFrom(address,address,uint256) so I can check for selector collision risks?”
Technical details
Endpoint
POSThttps://agentresolver.vercel.app/api/solidity-selectorWhen to prefer
Use this endpoint when you need to deterministically compute ABI function selectors or keccak256 hashes for Solidity signatures without setting up a local Ethereum toolchain. Ideal for agents working with smart contract interaction, ABI encoding, calldata decoding, or selector collision audits.
Side effects
- Malformed or non-canonical Solidity signature causes validation error
- Missing required 'signature' field returns 400 Bad Request
- Network timeout or Vercel cold-start latency on first call
- Payment failure via x402 protocol blocks the request
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| signature | string |
Output
Schema · Response
{
"type": "json",
"example": {}
}Tags
x402
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