> ## Documentation Index
> Fetch the complete documentation index at: https://www.helius.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# logsSubscribe

> Subscribe to transaction logging.

## Endpoints

Websockets are available on mainnet and devnet with the following URLs:

* **Mainnet** `wss://mainnet.helius-rpc.com/?api-key=<api-key>`
* **Devnet** `wss://devnet.helius-rpc.com/?api-key=<api-key>`

<Note>Websockets have a 10-minute inactivity timer; implementing health checks and sending pings every minute is heavily recommended to keep the websocket connection alive.</Note>

## Authorizations

<ParamField query="api-key" type="string" required>
  Your Helius API key. You can get one for free in the [dashboard](https://dashboard.helius.dev/api-keys).
</ParamField>

## Body

<ParamField body="params" type="array" required>
  <Expandable title="properties" defaultOpen>
    <ParamField body="filter" type="string | object" required>
      Filter criteria for the logs to receive results by account type. The following filters types are currently supported:

      * `all` - subscribe to all transactions except for simple vote transactions
      * `allWithVotes` - subscribe to all transactions, including simple vote transactions
      * A JSON object with the following field:
        * `mentions: [ <string> ]` - array containing a single Pubkey (as base-58 encoded string); if present, subscribe to only transactions mentioning this address

      Note: The `mentions` field currently only supports one Pubkey string per method call. Listing additional addresses will result in an error.
    </ParamField>

    <ParamField body="config" type="object">
      Configuration object containing the following fields:

      <ParamField body="commitment" type="string">
        The commitment level for the subscription. Can be `finalized`, `confirmed`, or `processed`.
      </ParamField>
    </ParamField>
  </Expandable>
</ParamField>

## Response

<ResponseField name="result" type="integer">
  Subscription id (needed to unsubscribe)
</ResponseField>

## Notification Format

The notification will be an RpcResponse JSON object with value equal to:

* `signature: <string>` - The transaction signature base58 encoded.
* `err: <object|null>` - Error if transaction failed, null if transaction succeeded. See TransactionError definitions.
* `logs: <array[string]>` - Array of log messages the transaction instructions output during execution.

<RequestExample>
  ```json Request theme={"system"}
  {
    "jsonrpc": "2.0",
    "id": 1,
    "method": "logsSubscribe",
    "params": [
      {
        "mentions": ["11111111111111111111111111111111"]
      },
      {
        "commitment": "finalized"
      }
    ]
  }
  ```
</RequestExample>

<ResponseExample>
  ```json Response theme={"system"}
  {
    "jsonrpc": "2.0",
    "result": 24040,
    "id": 1
  }
  ```

  ```json Notification theme={"system"}
  {
    "jsonrpc": "2.0",
    "method": "logsNotification",
    "params": {
      "result": {
        "context": {
          "slot": 5208469
        },
        "value": {
          "signature": "5h6xBEauJ3PK6SWCZ1PGjBvj8vDdWG3KpwATGy1ARAXFSDwt8GFXM7W5Ncn16wmqokgpiKRLuS83KUxyZyv2sUYv",
          "err": null,
          "logs": [
            "SBF program 83astBRguLMdt2h5U1Tpdq5tjFoJ6noeGwaY3mDLVcri success"
          ]
        }
      },
      "subscription": 24040
    }
  }
  ```
</ResponseExample>