keccak topic of an event signature API

Compute the keccak256 topic[0] for an event signature, e.g. Transfer(address,address,uint256), used to filter logs, via viem's toEventHash. Answers 'What topic do I filter for the Transfer event?','What is the keccak of this event signature?'.

Price$0.01per request

MethodPOST

Route/v1/evm/event-topic

StatusLive

MIME typeapplication/json

Rate limit60/minute

CacheNo cache

evmeventtopickeccaklogabisignature

API URLhttps://x402.hexl.dev/v1/evm/event-topic

Integration docs

Example request

{
  "signature": "Transfer(address,address,uint256)"
}

Example response

{
  "signature": "Transfer(address,address,uint256)",
  "topic": "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
}

Input schema

{
  "type": "object",
  "required": [
    "signature"
  ],
  "properties": {
    "signature": {
      "type": "string",
      "examples": [
        "Transfer(address,address,uint256)"
      ]
    }
  },
  "examples": [
    {
      "signature": "Transfer(address,address,uint256)"
    }
  ]
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}