Compute the 4-byte function/error selector and full keccak topic from a solidity...
https://api.x402node.dev/crypto/selectorOverview
Compute the 4-byte function/error selector and full keccak topic from a solidity signature, e.g. transfer(address,uint256). For decoding tx input prefixes and matching event topics. function selector, 4byte, method id, event topic, keccak signature
Protocol
x402
Price
$0.01
Payment Asset
USD Coin
Payment Network
eip155:8453
Category
crypto/transactions
Provider
x402node
Source
bazaar
Indexed
2026-06-21 22:15:28
Health
Status
healthy
Latency (p50)
647ms
Uptime (30d)
100.0%
Reliability Score
90/100
Last Checked
2026-10-31 07:04:12
Last Healthy
2026-10-31 07:04:12
Consecutive Failures
0
x402 Payment Validation
Payment Requirements
Valid
Asset Verified
Known USDC
Facilitator
—
Input Schema
{
"method": "GET",
"queryParams": {
"signature": "string"
},
"type": "http"
}