# eth_newFilter - Ethereum

Creates a filter object, based on filter options, to notify when the state changes (logs).

Unlike [eth\_newBlockFilter](https://unifra.readme.io/reference/eth_newblockfilter) which notifies you of all **new** blocks, you can pass in filter options to track new logs matching the topics specified.\
To check if the state has changed, call [eth\_getFilterChanges](https://unifra.readme.io/reference/eth_getfilterchanges)

> **A note on specifying topic filters:**\
> Topics are order-dependent. A transaction with a log with topics [A, B] will be matched by the following topic filters:
>
> * \[] “anything”
> * [A] “A in first position (and anything after)”
> * [null, B] “anything in first position AND B in second position (and anything after)”
> * [A, B] “A in first position AND B in second position (and anything after)”
> * \[[A, B], [A, B]] “(A OR B) in first position AND (A OR B) in second position (and anything after)”

# Parameters

* Object - The filter options:
  * fromBlock: QUANTITY|TAG - (optional, default: "latest") Integer block number, or "latest" for the last mined block or "pending", "earliest" for not yet mined transactions.
  * toBlock: QUANTITY|TAG - (optional, default: "latest") Integer block number, or "latest" for the last mined block or "pending", "earliest" for not yet mined transactions.
  * address: DATA|Array, 20 Bytes - (optional) Contract address or a list of addresses from which logs should originate.
  * topics: Array of DATA, - (optional) Array of 32 Bytes DATA topics. Topics are order-dependent. Each topic can also be an array of DATA with “or” options.

```json
params: [
	{
		fromBlock: "0x1",
		toBlock: "0x2",
		address: "0x8888f1f195afa192cfee860698584c030f4c9db1",
		topics: [
			"0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b",
			null,
			[
				"0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b",
				"0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc",
			],
		],
	},
];
```

***

# Returns

QUANTITY - A filter id.

***

# Example

## Request

```curl
curl https://eth-mainnet.unifra.io/v1/your-api-key \
-X POST \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","method":"eth_newFilter","params":[{"fromBlock": "0x1","toBlock": "0x2","address": "0x8888f1f195afa192cfee860698584c030f4c9db1","topics": ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", null, ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", "0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc"]]}],"id":0}'
```
```Text Postman
URL: https://eth-mainnet.unifra.io/v1/your-api-key
RequestType: POST
Body:
{
    "jsonrpc":"2.0",
    "method":"eth_newFilter",
    "params":[{"fromBlock": "0x1","toBlock": "0x2","address": "0x8888f1f195afa192cfee860698584c030f4c9db1","topics": ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", null, ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", "0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc"]]}],
    "id":0
}
```

## Result

```json
{
	"jsonrpc": "2.0",
	"id": 0,
	"result": "0xdcc9a819f80efa9e1d215a9d41b2d22e"
}
```

> 🚧 The below parameter inputs do not work, please reference the section above instead.

# OpenAPI definition

```json
{
  "openapi": "3.1.0",
  "info": {
    "title": "ethereum-api",
    "version": "1.0"
  },
  "servers": [
    {
      "url": "https://eth-mainnet.unifra.io/v1"
    }
  ],
  "security": [
    {}
  ],
  "paths": {
    "/{your-api-key}": {
      "post": {
        "summary": "web3_sha3 - Ethereum",
        "description": "Returns Keccak-256 (not the standardized SHA3-256) of the given data.",
        "operationId": "web3_sha3",
        "parameters": [
          {
            "name": "your-api-key",
            "in": "path",
            "schema": {
              "type": "string"
            },
            "required": true
          }
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "type": "object",
                "properties": {
                  "jsonrpc": {
                    "type": "string",
                    "default": "2.0"
                  },
                  "method": {
                    "type": "string",
                    "default": "web3_sha3"
                  },
                  "params": {
                    "type": "array",
                    "items": {
                      "type": "string"
                    }
                  },
                  "id": {
                    "type": "integer",
                    "default": 0,
                    "format": "int32"
                  }
                }
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "200",
            "content": {
              "application/json": {
                "examples": {
                  "Result": {
                    "value": "{}"
                  }
                },
                "schema": {
                  "type": "object",
                  "properties": {}
                }
              }
            }
          },
          "400": {
            "description": "400",
            "content": {
              "application/json": {
                "examples": {
                  "Result": {
                    "value": "{}"
                  }
                },
                "schema": {
                  "type": "object",
                  "properties": {}
                }
              }
            }
          }
        },
        "deprecated": false
      }
    }
  },
  "x-readme": {
    "headers": [],
    "explorer-enabled": true,
    "proxy-enabled": true
  },
  "x-readme-fauxas": true
}
```