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Compute the 4-byte function/error selector and full keccak topic from a solidity...

https://api.x402node.dev/crypto/selector

Overview

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
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) 417ms
Uptime (30d) 100.0%
Reliability Score 95/100
Last Checked 2026-08-06 09:35:05
Last Healthy 2026-08-06 09:35:05
Consecutive Failures 0

x402 Payment Validation

Payment Requirements Valid
Asset Verified Known USDC
Facilitator

Recent Health Checks

Time Status HTTP Latency Error
2026-08-06 09:35:05 healthy 402 428ms
2026-08-06 05:16:17 healthy 402 418ms
2026-08-05 22:09:36 healthy 402 416ms
2026-08-05 16:33:16 healthy 402 142ms
2026-08-05 14:44:11 healthy 402 141ms
2026-08-05 07:41:00 healthy 402 434ms
2026-08-05 03:33:22 healthy 402 417ms
2026-08-04 22:52:19 healthy 402 420ms
2026-08-04 14:39:30 healthy 402 417ms
2026-08-04 11:37:31 healthy 402 413ms
2026-08-04 08:02:42 healthy 402 418ms
2026-08-04 02:32:09 healthy 402 425ms
2026-08-03 19:46:49 healthy 402 414ms
2026-08-03 16:58:26 healthy 402 414ms