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# eth_newFilter

# `eth_newFilter`

Creates a log filter and returns a filter ID. Use the ID with [`eth_getFilterChanges`](/api/reference/eth-getfilterchanges) to poll for new logs, or [`eth_getFilterLogs`](/api/reference/eth-getfilterlogs) to read all matching logs at once.

Filter polling on the public endpoint

Filter IDs are server-side state, scoped to the node that created them. On a load-balanced public endpoint like `rpc.linea.build`, a follow-up `eth_getFilterChanges` or `eth_getFilterLogs` request may land on a different backend that has no record of the filter and silently return an empty result. For reliable event consumption in production, use [`eth_getLogs`](/api/reference/eth-getlogs) with explicit block ranges, or a private RPC endpoint with sticky sessions.

## Parameters

-   `filter`: _[required]_ Filter object (same shape as [`eth_getLogs`](/api/reference/eth-getlogs)):
    -   `fromBlock`: _[optional]_ Hexadecimal block number, or `latest`, `earliest`. The default is `latest`.
    -   `toBlock`: _[optional]_ Hexadecimal block number, or `latest`, `earliest`. The default is `latest`.
    -   `address`: _[optional]_ Contract address or array of addresses.
    -   `topics`: _[optional]_ Array of 32-byte topic values. Each position can be a single value, an array of values (OR), or `null` (wildcard).

## Returns

A filter ID (hexadecimal string).

## Example

### Request

```bash
curl https://rpc.linea.build \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_newFilter",
    "params": [
      {
        "address": "0x176211869ca2b568f2a7d4ee941e073a821ee1ff",
        "topics": [
          "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
        ]
      }
    ],
    "id": 1
  }'
```

### Response

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x10ff687202f305efab..."
}
```