eth_getFilterChanges

Polling method for a filter on Moonbase Alpha, returns an array of logs since last poll.

Use Cases

• Event streaming - Get new events incrementally
• Real-time monitoring - Track contract activity for EVM dApp testing, XCM integration validation, and pre-mainnet deployment verification
• Efficient indexing - Process only new events

Parameters

Parameter	Type	Required	Description
filterId	QUANTITY	Yes	Filter ID from eth_newFilter

Request

{
  "jsonrpc": "2.0",
  "method": "eth_getFilterChanges",
  "params": ["0x1"],
  "id": 1
}

Code Examples

cURL

curl -X POST https://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_getFilterChanges",
    "params": ["0x1"],
    "id": 1
  }'

JavaScript

import { JsonRpcProvider } from 'ethers';

const provider = new JsonRpcProvider('https://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY');

// Poll loop
async function pollFilter(filterId, interval = 2000) {
  while (true) {
    const changes = await provider.send('eth_getFilterChanges', [filterId]);
    if (changes.length > 0) {
      console.log('New events:', changes);
    }
    await new Promise(r => setTimeout(r, interval));
  }
}

Related Methods

• eth_newFilter - Create filter
• eth_uninstallFilter - Remove filter