# Filter

### klay\_getFilterChanges <a href="#klay_getfilterchanges" id="klay_getfilterchanges"></a>

Polling method for a filter, which returns an array of logs which occurred since last poll.

**Parameters**

| Name     | Type   | Description                           |
| -------- | ------ | ------------------------------------- |
| QUANTITY | string | The filter id (*e.g.*, "0x16" // 22). |

**Return Value**

`Array` - Array of log objects, or an empty array if nothing has changed since last poll.

* For filters created with [klay\_newBlockFilter](#klay_newblockfilter), the return are block hashes (32-byte DATA), *e.g.*, `["0x3454645634534..."]`.
* For filters created with [klay\_newPendingTransactionFilter](#klay_newpendingtransactionfilter), the return are transaction hashes (32-byte DATA), *e.g.*, `["0x6345343454645..."]`.
* For filters created with [klay\_newFilter](#klay_newfilter), logs are objects with following parameters:

| Name             | Type          | Description                                                                                                                                                                                                                                  |
| ---------------- | ------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| removed          | TAG           | `true` when the log was removed, due to a chain reorganization. `false` if it is a valid log.                                                                                                                                                |
| logIndex         | QUANTITY      | Integer of the log index position in the block. `null` when it is a pending log.                                                                                                                                                             |
| transactionIndex | QUANTITY      | Integer of the transactions index position log was created from. `null` when pending.                                                                                                                                                        |
| transactionHash  | 32-byte DATA  | Hash of the transactions this log was created from. `null` when pending.                                                                                                                                                                     |
| blockHash        | 32-byte DATA  | Hash of the block where this log was in. `null` when pending.                                                                                                                                                                                |
| blockNumber      | QUANTITY      | The block number where this log was in. `null` when pending.                                                                                                                                                                                 |
| address          | 20-byte DATA  | Address from which this log originated.                                                                                                                                                                                                      |
| data             | DATA          | Contains the non-indexed arguments of the log.                                                                                                                                                                                               |
| topics           | Array of DATA | Array of 0 to 4 32-byte DATA of indexed log arguments. (In Solidity: The first topic is the hash of the signature of the event (*e.g.*, `Deposit(address,bytes32,uint256)`), except you declared the event with the `anonymous` specifier.). |

**Example**

```shell
// Request
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_getFilterChanges","params":["0x16"],"id":73}' https://public-en-baobab.klaytn.net

// Result
{
    "id":1,
    "jsonrpc":"2.0",
    "result": [{
    "logIndex": "0x1", // 1
    "blockNumber":"0x1b4", // 436
    "blockHash": "0x8216c5785ac562ff41e2dcfdf5785ac562ff41e2dcfdf829c5a142f1fccd7d",
    "transactionHash":  "0xdf829c5a142f1fccd7d8216c5785ac562ff41e2dcfdf5785ac562ff41e2dcf",
    "transactionIndex": "0x0", // 0
    "address": "0x16c5785ac562ff41e2dcfdf829c5a142f1fccd7d",
    "data":"0x0000000000000000000000000000000000000000000000000000000000000000",
    "topics": ["0x59ebeb90bc63057b6515673c3ecf9438e5058bca0f92585014eced636878c9a5"]
    },{
        ...
    }]
}
```

### klay\_getFilterLogs <a href="#klay_getfilterlogs" id="klay_getfilterlogs"></a>

Returns an array of all logs matching filter with given id, which has been obtained using [klay\_newFilter](#klay_newfilter). Note that filter ids returned by other filter creation functions, such as [klay\_newBlockFilter](#klay_newblockfilter) or [klay\_newPendingTransactionFilter](#klay_newpendingtransactionfilter), cannot be used with this function.

The execution of this API can be limited by two node configurations to manage resources of Klaytn node safely.

* The number of maximum returned results in a single query (Default: 10,000).
* The execution duration limit of a single query (Default: 10 seconds).

**Parameters**

| Name     | Type   | Description   |
| -------- | ------ | ------------- |
| QUANTITY | string | The filter id |

**Return Value**

See [klay\_getFilterChanges](#klay_getfilterchanges)

**Example**

```shell
// Request
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_getFilterLogs","params":["0xd32fd16b6906e67f6e2b65dcf48fc272"],"id":1}' https://public-en-baobab.klaytn.net

// Result
{
  "jsonrpc":"2.0",
  "id":1,
  "result":[{
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xd596fdad182d29130ce218f4c1590c4b5ede105bee36690727baa6592bd2bfc8"],
      "data":"0x0000000000000000000000000000000000000000000000000000000000000064000000000000000000000000000000000000000000000000000000000000007b",
      "blockNumber":"0x54",
      "transactionHash":"0xcd4703cd62bd930d4652999bce8dcb75b7ade49d922fa42dc11e568c52a5fa6f",
      "transactionIndex":"0x0",
      "blockHash":"0x9a49f30f1d1876ff3913bd0aa58f328822e7a369cb13e0640b82234f26e781bb",
      "logIndex":"0x0",
      "removed":false
  }]
}
```

### klay\_getLogs <a href="#klay_getlogs" id="klay_getlogs"></a>

Returns an array of all logs matching a given filter object.

The execution of this API can be limited by two node configurations to manage resources of Klaytn node safely.

* The number of maximum returned results in a single query (Default: 10,000).
* The execution duration limit of a single query (Default: 10 seconds).

**Parameters**

`Object` - The filter options:

| Name      | Type                  | Description                                                                                                                                                                                                                                                                                                      |
| --------- | --------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| fromBlock | QUANTITY \| TAG       | (optional, default: `"latest"`) Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter).                                                                 |
| toBlock   | QUANTITY \| TAG       | (optional, default: `"latest"`) Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter).                                                                 |
| address   | 20-byte DATA \| Array | (optional) Contract address or a list of addresses from which logs should originate.                                                                                                                                                                                                                             |
| topics    | Array of DATA         | (optional) Array of 32-byte DATA topics. Topics are order-dependent. Each topic can also be an array of DATA with “or” options.                                                                                                                                                                                  |
| blockHash | 32-byte DATA          | (optional) A filter option that restricts the logs returned to the single block with the 32-byte hash blockHash. Using blockHash is equivalent to fromBlock = toBlock = the block number with hash blockHash. If blockHash is present in in the filter criteria, then neither fromBlock nor toBlock are allowed. |

{% hint style="success" %}
NOTE: In versions earlier than Klaytn v1.7.0, only integer block number, the string `"earliest"` and `"latest"` are available.
{% endhint %}

**Return Value**

See [klay\_getFilterChanges](#klay_getfilterchanges)

**Examples**

```shell
// Request
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_getLogs","params":[{"fromBlock":"0x1","toBlock":"latest","address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b"}],"id":1}' https://public-en-baobab.klaytn.net

// Result
{
  "jsonrpc":"2.0",
  "id":1,
  "result":[
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xfa9b2165fc71c1d6ffa03291c7f5d223ea363ec063d747eec9ce2d30d24855ef"],
      "data":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000060000000000000000000000000d3564e57bb5c6f4d983a493a946534f8e1e8b481000000000000000000000000000000000000000000000000000000000000001341646472657373426f6f6b436f6e747261637400000000000000000000000000",
      "blockNumber":"0xd3b5",
      "transactionHash":"0x57ca8ff0a0d454d4c5418694c21bc4ef3de26cf7cd18dd404d6a7189a826bfe0",
      "transactionIndex":"0x0",
      "blockHash":"0x279251a907c6ab1fb723595511ff401432e7c2437d54189298f53a7d33ce3a60",
      "logIndex":"0x0",
      "removed":false
    },
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xfa3e1e272694072320aad73a3fadd8876c4bf8f40899c6c7ce2fda9f4e652cfa"],
      "data":"0x00000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000003000000000000000000000000000000000000000000000000000000000000000300000000000000000000000041383b6ee0ea5108d6b139165a9c85351aacd39800000000000000000000000057f7439898e652fa9b5654022297588532e5e0370000000000000000000000005b5b7a718a4124eb746ae00b1ce6edcaa5ab55bc",
      "blockNumber":"0xd3b5",
      "transactionHash":"0x57ca8ff0a0d454d4c5418694c21bc4ef3de26cf7cd18dd404d6a7189a826bfe0",
      "transactionIndex":"0x0",
      "blockHash":"0x279251a907c6ab1fb723595511ff401432e7c2437d54189298f53a7d33ce3a60",
      "logIndex":"0x1",
      "removed":false
    },
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xc7b359b1e189b7d721be7f0765a8d745be718566b8e67cbd2728dae5d6fd64b6"],
      "data":"0x000000000000000000000000d3564e57bb5c6f4d983a493a946534f8e1e8b481000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000600000000000000000000000000000000000000000000000000000000000000003000000000000000000000000286d09b578d6126e09296dfe6c775ea7d0cf06e9000000000000000000000000860350f6d774efd16046335c388b832b910d3f8c00000000000000000000000061a7cbdd597848494fa85cbb76f9c63ad9c06cad",
      "blockNumber":"0x14d96",
      "transactionHash":"0x73282602d2f908180f47e3c8673f41c0899cbbb2d606976c2f77188ffa57d6e7",
      "transactionIndex":"0x0",
      "blockHash":"0xa5268a093cd5df7eccde18217a7019a35ab761088312027af16682aafa704ee3",
      "logIndex":"0x1",
      "removed":false
    },
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xc7b359b1e189b7d721be7f0765a8d745be718566b8e67cbd2728dae5d6fd64b6"],
      "data":"0x000000000000000000000000d3564e57bb5c6f4d983a493a946534f8e1e8b4810000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000006000000000000000000000000000000000000000000000000000000000000000030000000000000000000000002f91d1b79dd06da1b622122d61e05e64562de61e0000000000000000000000006e76e0ce76dfba55060400144318d4821a58510600000000000000000000000031b93ca83b5ad17582e886c400667c6f698b8ccd",
      "blockNumber":"0x14e4e",
      "transactionHash":"0xf9d86ed451d67abc68c517f7fa0e0a7a8e3dedec23f56febda2b7f52d35185b6",
      "transactionIndex":"0x0",
      "blockHash":"0x7ddf4a0a203d40afc1706aa24b787da601e1bce326319349d0eeef6c41656fa5",
      "logIndex":"0x1",
      "removed":false
    }
  ]
}
```

```shell
// Request
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_getLogs","params":[{"fromBlock":"earliest","toBlock":"latest","topics":["0xc7b359b1e189b7d721be7f0765a8d745be718566b8e67cbd2728dae5d6fd64b6"]}],"id":2}' https://public-en-baobab.klaytn.net

// Result
{
  "jsonrpc":"2.0",
  "id":2,
  "result":[
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xc7b359b1e189b7d721be7f0765a8d745be718566b8e67cbd2728dae5d6fd64b6"],
      "data":"0x000000000000000000000000d3564e57bb5c6f4d983a493a946534f8e1e8b481000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000600000000000000000000000000000000000000000000000000000000000000003000000000000000000000000286d09b578d6126e09296dfe6c775ea7d0cf06e9000000000000000000000000860350f6d774efd16046335c388b832b910d3f8c00000000000000000000000061a7cbdd597848494fa85cbb76f9c63ad9c06cad",
      "blockNumber":"0x14d96",
      "transactionHash":"0x73282602d2f908180f47e3c8673f41c0899cbbb2d606976c2f77188ffa57d6e7",
      "transactionIndex":"0x0",
      "blockHash":"0xa5268a093cd5df7eccde18217a7019a35ab761088312027af16682aafa704ee3",
      "logIndex":"0x1",
      "removed":false
    },
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xc7b359b1e189b7d721be7f0765a8d745be718566b8e67cbd2728dae5d6fd64b6"],
      "data":"0x000000000000000000000000d3564e57bb5c6f4d983a493a946534f8e1e8b4810000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000006000000000000000000000000000000000000000000000000000000000000000030000000000000000000000002f91d1b79dd06da1b622122d61e05e64562de61e0000000000000000000000006e76e0ce76dfba55060400144318d4821a58510600000000000000000000000031b93ca83b5ad17582e886c400667c6f698b8ccd",
      "blockNumber":"0x14e4e",
      "transactionHash":"0xf9d86ed451d67abc68c517f7fa0e0a7a8e3dedec23f56febda2b7f52d35185b6",
      "transactionIndex":"0x0",
      "blockHash":"0x7ddf4a0a203d40afc1706aa24b787da601e1bce326319349d0eeef6c41656fa5",
      "logIndex":"0x1",
      "removed":false
    },
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xc7b359b1e189b7d721be7f0765a8d745be718566b8e67cbd2728dae5d6fd64b6"],
      "data":"0x000000000000000000000000d3564e57bb5c6f4d983a493a946534f8e1e8b481000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000600000000000000000000000000000000000000000000000000000000000000003000000000000000000000000a2b1264624c92257dd8e7f0cac42d451061d1510000000000000000000000000b381ee81e319e5ec48f42d0b47b5e4361c9a6f740000000000000000000000003855407fa65c4c5104648b3a9e495072df62b585",
      "blockNumber":"0x14f38",
      "transactionHash":"0xc8f8c637ea9fcbe71e23fe0779b59fb10173e8c4fd7e49bce3cce76ff67d353d",
      "transactionIndex":"0x0",
      "blockHash":"0xb1717038e443f517bd7a8c37b66fb731fed573f5fa5486ebbbb5e4c9060be50b",
      "logIndex":"0x1",
      "removed":false
    },
    {
      "address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b",
      "topics":["0xc7b359b1e189b7d721be7f0765a8d745be718566b8e67cbd2728dae5d6fd64b6"],
      "data":"0x000000000000000000000000d3564e57bb5c6f4d983a493a946534f8e1e8b4810000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000006000000000000000000000000000000000000000000000000000000000000000030000000000000000000000009dd579f23912665b956b0cd50387b29a62052732000000000000000000000000c98a86af2eca2989c0cb2a2b8d4bb841f11e94ab000000000000000000000000f65e07b6626ab43ecea744803fa46bd4a89bfdb6",
      "blockNumber":"0x14fe7",
      "transactionHash":"0x14da1883bb2aae487ce1cb93cd39bc9bb802adbba083f337051877358150ab3f",
      "transactionIndex":"0x0",
      "blockHash":"0xcd820189f00e9a6faaea7313437b92114e69bd32e18b4a28e7763117716c6fa9",
      "logIndex":"0x1",
      "removed":false
    }
  ]
}
```

### klay\_newBlockFilter <a href="#klay_newblockfilter" id="klay_newblockfilter"></a>

Creates a filter in the node, to notify when a new block arrives. To check if the state has changed, call [klay\_getFilterChanges](#klay_getfilterchanges).

**Parameters**

None

**Return Value**

| Type     | Description  |
| -------- | ------------ |
| QUANTITY | A filter id. |

**Example**

```shell
// Request
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_newBlockFilter","params":[],"id":73}' https://public-en-baobab.klaytn.net

// Result
{
  "jsonrpc":"2.0",
  "id":73,
  "result":"0xc2f2e8168a7e38b5d979d0f7084130ee"
}
```

### klay\_newFilter <a href="#klay_newfilter" id="klay_newfilter"></a>

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

* To check if the state has changed, call [klay\_getFilterChanges](#klay_getfilterchanges).
* To obtain all logs matching the filter created by `klay_newFilter`, call [klay\_getFilterLogs](#klay_getfilterlogs).

**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:

| Name      | Type                  | Description                                                                                                                                                                                                                                      |
| --------- | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| fromBlock | QUANTITY \| TAG       | (optional, default: `"latest"`) Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter). |
| toBlock   | QUANTITY \| TAG       | (optional, default: `"latest"`) Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter). |
| address   | 20-byte DATA \| Array | (optional) Contract address or a list of addresses from which logs should originate.                                                                                                                                                             |
| topics    | Array of DATA         | (optional) Array of 32-byte DATA topics. Topics are order-dependent. Each topic can also be an array of DATA with "or" options.                                                                                                                  |

{% hint style="success" %}
NOTE: In versions earlier than Klaytn v1.7.0, only integer block number, the string `"earliest"` and `"latest"` are available.
{% endhint %}

**Return Value**

| Type     | Description |
| -------- | ----------- |
| QUANTITY | A filter id |

**Example**

```shell
// Request
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_newFilter","params":[{"fromBlock":"earliest","toBlock":"latest","address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b","topics":["0xd596fdad182d29130ce218f4c1590c4b5ede105bee36690727baa6592bd2bfc8"]}],"id":1}' https://public-en-baobab.klaytn.net

// Result
{"jsonrpc":"2.0","id":1,"result":"0xd32fd16b6906e67f6e2b65dcf48fc272"}
```

### klay\_newPendingTransactionFilter <a href="#klay_newpendingtransactionfilter" id="klay_newpendingtransactionfilter"></a>

Creates a filter in the node, to notify when new pending transactions arrive. To check if the state has changed, call [klay\_getFilterChanges](#klay_getfilterchanges).

**Parameters**

None

**Return Value**

| Type     | Description  |
| -------- | ------------ |
| QUANTITY | A filter id. |

**Example**

```shell
// Request
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_newPendingTransactionFilter","params":[],"id":73}' https://public-en-baobab.klaytn.net

// Result
{
  "jsonrpc":"2.0",
  "id":73,
  "result":"0x90cec22a723fcc725fb2462733c2880f"
}
```

### klay\_subscribe <a href="#klay_subscribe" id="klay_subscribe"></a>

Creates a new subscription to specific events by using either RPC Pub/Sub over WebSockets or filters over HTTP. It allows clients to wait for events instead of polling for them.

The node will return a subscription id for each subscription created. For each event that matches the subscription, a notification with relevant data is sent together with the subscription id. If a connection is closed, all subscriptions created over the connection are removed.

**Parameters**

`Object` - A notification type: `"newHeads"` or `"logs"`.

`"newHeads"` notifies you of each block added to the blockchain. `"logs"` notifies you of logs included in new blocks. This type requires a second parameter that specifies filter options. For more details, go to [klay\_newFilter > parameters](https://docs.klaytn.com/dapp/json-rpc/api-references/klay/filter#klay_newfilter).

**Return Value**

| Type     | Description                                                                                                                                                  |
| -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| QUANTITY | A subscription id when a subscription is created. For each event that matches the subscription, a notification with relevant data will be delivered as well. |

**Example**

This API is appropriate for use with a WebSocket tool, [`wscat`](https://www.npmjs.com/package/wscat).

```shell
// Request
wscat -c http://localhost:8552
> {"jsonrpc":"2.0", "id": 1, "method": "klay_subscribe", "params": ["newHeads"]}

// Result
< {"jsonrpc":"2.0","id":1,"result":"0x48bb6cb35d6ccab6eb2b4799f794c312"}
< {"jsonrpc":"2.0","method":"klay_subscription","params":{"subscription":"0x48bb6cb35d6ccab6eb2b4799f794c312","result":{"parentHash":"0xc39755b6ac01d1e8c58b1088e416204f7af5b6b66bfb4f474523292acbaa7d57","reward":"0x2b2a7a1d29a203f60e0a964fc64231265a49cd97","stateRoot":"0x12aa1d3ab0440d844c28fbc6f89d26082f39a8435b512fa487ff55c2056aceb3","number":"0x303bea4”, ... ... }}}
```

```shell
// Request
wscat -c http://localhost:8552
> {"jsonrpc":"2.0", "id": 1, "method": "klay_subscribe", "params": ["logs", {"fromBlock":"earliest","toBlock":"latest","address":"0x87ac99835e67168d4f9a40580f8f5c33550ba88b","topics":["0xd596fdad182d29130ce218f4c1590c4b5ede105bee36690727baa6592bd2bfc8"]}]}

// Result
< {"jsonrpc":"2.0","id":1,"result":"0xbdab16c8e4ae1b9e6930c78359de3e0e"}
< {"jsonrpc":"2.0","method":"klay_subscription","params":{"subscription":"0xbdab16c8e4ae1b9e6930c78359de3e0e","result":{"address":"0x2e4bb340e26caffb4073d7f1151f37d17524cdbc","topics":["0xb1a7310b1a46c788fcf30784cad70442d5232acaef480b0c094c76bee8d9c77d"],"data":"0x0000000000000000000000000000000000000000000000000000000000000040000000000000000000000000d2588fe96a34c56a5d0a484cb603bc16fc5cdbbc","blockNumber":"0x3041201","transactionHash":"0xdacdebc77006fc566f65448524a0bc770056d8c7a05244bc7bfb2123b1bd398c","transactionIndex":"0x0","blockHash":"0x899b2dbfe96a34ce5d965dbcfcf39d072b4ce1097d479923e6b6355f3e2609ec","logIndex":"0x0","removed":false}}}
```

### klay\_uninstallFilter <a href="#klay_uninstallfilter" id="klay_uninstallfilter"></a>

Uninstalls a filter with given id. Should always be called when watch is no longer needed. Additionally, filters timeout when they are not requested with [klay\_getFilterChanges](#klay_getfilterchanges) for a period of time.

**Parameters**

| Name   | Type     | Description  |
| ------ | -------- | ------------ |
| filter | QUANTITY | A filter id. |

**Return Value**

| Type    | Description                                                           |
| ------- | --------------------------------------------------------------------- |
| Boolean | `true` if the filter was successfully uninstalled, otherwise `false`. |

**Example**

```shell
// Request
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_uninstallFilter","params":["0xb"],"id":73}' https://public-en-baobab.klaytn.net

// Result
{
  "jsonrpc": "2.0",
  "id":1,
  "result": true
}
```

### klay\_unsubscribe <a href="#klay_unsubscribe" id="klay_unsubscribe"></a>

Cancels the subscription with a specific subscription id by using either RPC Pub/Sub over WebSockets or filters over HTTP. Only the connection that created a subscription can unsubscribe from it.

**Parameters**

| Type     | Description        |
| -------- | ------------------ |
| QUANTITY | A subscription id. |

**Return Value**

| Type    | Description                                                              |
| ------- | ------------------------------------------------------------------------ |
| Boolean | `true` if the subscription was successfully canceled, otherwise `false`. |

**Example**

This API is appropriate for use with a WebSocket tool, [`wscat`](https://www.npmjs.com/package/wscat).

```shell
// Request
> {"jsonrpc":"2.0", "id": 1, "method": "klay_unsubscribe", "params": ["0xab8ac7a4045025d0c2807d63060eea6d"]}

// Result
< {"jsonrpc":"2.0","id":1,"result":true}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://archive-docs.klaytn.foundation/content/dapp/json-rpc/api-references/klay/filter.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.