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POST
eth_newBlockFilter
curl --request POST \
  --url https://tempo-moderato.core.chainstack.com/a25a421add2280d53fdbc23417055501/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "jsonrpc": "2.0",
  "method": "eth_newBlockFilter",
  "params": [],
  "id": 1
}
'
{
  "jsonrpc": "<string>",
  "id": 123,
  "result": "<string>"
}
Tempo API method that creates a filter for new block notifications. The filter can be polled with eth_getFilterChanges to get new block hashes.
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With Tempo’s ~0.5 second block times, this filter will receive frequent updates.

​
Parameters

  • none

​
Response

  • result — the filter ID

​
eth_newBlockFilter code examples

const ethers = require('ethers');
const NODE_URL = "CHAINSTACK_NODE_URL";
const provider = new ethers.JsonRpcProvider(NODE_URL);

const createBlockFilter = async () => {
    const filterId = await provider.send("eth_newBlockFilter", []);
    console.log(`Filter ID: ${filterId}`);

    // Poll for new blocks
    const newBlocks = await provider.send("eth_getFilterChanges", [filterId]);
    console.log(`New block hashes: ${newBlocks}`);
  };

createBlockFilter();

Body

application/json
​
jsonrpc
string
default:2.0
​
method
string
default:eth_newBlockFilter
​
params
any[]
​
id
integer
default:1

Response

200 - application/json

The filter ID

​
jsonrpc
string
​
id
integer
​
result
string

The filter ID for new block notifications

Last modified on January 23, 2026