Filter Events

Filter blockchain events based on specified criteria.

Endpoint

POST /filterEvent

Description

Filters blockchain events based on specified criteria including event name, contract addresses, block ranges, and field values.

Request Body

{
  "contracts": ["0x96AF30413A6999f9948c7c88b0dFf8B56Bf31EF6"],
  "eventName": "Transfer",
  "eventDef": "event Transfer(address indexed from, address indexed to, uint256 value)",
  "fields": {
    "from": "0x0000000000000000000000000000000000000000",
    "to": ["0x106eB473f541E9485bB428aeC502c2FEa1467779"]
  },
  "fromBlock": "0x0",
  "toBlock": "latest",
  "rpc": "https://polygon-amoy.infura.io/v3/{key}"
}

Response

{
  "requestStatus": 200,
  "txHashes": [
    "0x81eb1ce8c61a966a1a9ca84bf3701f934977d36e76f5b255c43478a3d59936e0"
  ]
}

Response Fields

requestStatus (integer): HTTP status code of the request
txHashes (array): Array of transaction hashes containing the filtered events

Example Request

curl -X POST https://api.msa.omnes.tech/filterEvent \
  -H "Content-Type: application/json" \
  -d '{
    "contracts": ["0x96AF30413A6999f9948c7c88b0dFf8B56Bf31EF6"],
    "eventName": "Transfer",
    "eventDef": "event Transfer(address indexed from, address indexed to, uint256 value)",
    "fields": {
      "from": "0x0000000000000000000000000000000000000000",
      "to": ["0x106eB473f541E9485bB428aeC502c2FEa1467779"]
    },
    "fromBlock": "0x0",
    "toBlock": "latest",
    "rpc": "https://polygon-amoy.infura.io/v3/{key}"
  }'

const response = await fetch('https://api.msa.omnes.tech/filterEvent', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    contracts: ['0x96AF30413A6999f9948c7c88b0dFf8B56Bf31EF6'],
    eventName: 'Transfer',
    eventDef: 'event Transfer(address indexed from, address indexed to, uint256 value)',
    fields: {
      from: '0x0000000000000000000000000000000000000000',
      to: ['0x106eB473f541E9485bB428aeC502c2FEa1467779'],
    },
    fromBlock: '0x0',
    toBlock: 'latest',
    rpc: 'https://polygon-amoy.infura.io/v3/{key}',
  }),
});

const result = await response.json();
console.log('Found transactions:', result.txHashes.length);

import requests

url = "https://api.msa.omnes.tech/filterEvent"
payload = {
    "contracts": ["0x96AF30413A6999f9948c7c88b0dFf8B56Bf31EF6"],
    "eventName": "Transfer",
    "eventDef": "event Transfer(address indexed from, address indexed to, uint256 value)",
    "fields": {
        "from": "0x0000000000000000000000000000000000000000",
        "to": ["0x106eB473f541E9485bB428aeC502c2FEa1467779"]
    },
    "fromBlock": "0x0",
    "toBlock": "latest",
    "rpc": "https://polygon-amoy.infura.io/v3/{key}"
}

response = requests.post(url, json=payload)
result = response.json()
print(f"Found transactions: {len(result['txHashes'])}")

Use Cases

Event monitoring: Track specific contract events
Transaction discovery: Find transactions containing specific events
Analytics: Analyze event patterns across contracts
Notification systems: Trigger actions based on events

Best Practices

Use indexed fields: Filter on indexed event fields for better performance
Limit block ranges: Use specific block ranges instead of scanning entire chain
Add event ABIs: Use add event ABI endpoint to register custom events
Handle large result sets: Paginate results for large event sets

Add Event ABI - Register custom event ABIs
Get Receipt - Get full transaction details with decoded logs

💡 Tip: Register custom event ABIs using the add event ABI endpoint to filter events from any contract, even if not pre-registered.

Filter Events

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