eth_newFilter on Ethereum
Creates a server-side log filter and returns its id, which you then poll with eth_getFilterChanges. Stateful; needs a free API key.
The filter id is pinned to one node's memory, so it doesn't work reliably behind a multi-node load balancer without sticky routing. For durable indexing, prefer repeated eth_getLogs with your own block cursor.
Ethereum endpoint (keyed — free)
https://rpc.nodeflare.app/eth/v1/YOUR_KEYMethod
eth_newFilter
Cost
20 CU
Chain ID
1
Block time
~12 s
Finality
~13 min (finalized)
Logs & events on Ethereum
Mainnet DeFi log density is high. Keep eth_getLogs windows to a few thousand blocks with tight address + topic filters — wide unfiltered ranges are the most common cause of slow queries, and each call costs 75 CU.
Parameters
[{ fromBlock, toBlock, address, topics[] }]cURL
curl https://rpc.nodeflare.app/eth/v1/YOUR_KEY \
-X POST \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","method":"eth_newFilter","params":[{"fromBlock": "latest", "toBlock": "latest"}],"id":1}'ethers.js
import { ethers } from 'ethers';
const provider = new ethers.JsonRpcProvider(
'https://rpc.nodeflare.app/eth/v1/YOUR_KEY'
);
const result = await provider.send('eth_newFilter', [{"fromBlock": "latest", "toBlock": "latest"}]);Try it live
Runs the example above against the public Ethereum endpoint — straight from your browser.
eth_newFilter on Ethereum — FAQ
How do I call eth_newFilter on Ethereum?
POST a JSON-RPC 2.0 request with "method": "eth_newFilter" to NodeFlare's Ethereum endpoint at https://rpc.nodeflare.app/eth/v1/YOUR_KEY. This method requires a free API key — it is not available on the public endpoint.
What does eth_newFilter cost on the free tier?
eth_newFilter is weighted at 20 compute units per call. The free tier includes 2,000,000 CU/month, so that is roughly 100,000 eth_newFilter calls per month — no credit card.
Is eth_newFilter available on the public Ethereum endpoint?
No. eth_newFilter is a heavy method and requires a free API key. The public no-key endpoint serves standard read methods; create a free key to unlock eth_newFilter, eth_getLogs, trace_* and debug_*.
Anything Ethereum-specific to know when using eth_newFilter?
Mainnet DeFi log density is high. Keep eth_getLogs windows to a few thousand blocks with tight address + topic filters — wide unfiltered ranges are the most common cause of slow queries, and each call costs 75 CU.
Call eth_newFilter on Ethereum with a free key
2,000,000 compute units/month, heavy methods unlocked, every chain included. No credit card.
Get your free API key →