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

# eth_subscribe ("logs") | Gnosis

> Subscribe to real-time Gnosis Chain event logs via WebSocket. Receive notifications whenever new logs matching your specified filter criteria are emitted.

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## Parameters

* `string` — keyword identifying the type of event to subscribe to, `logs` in this case.

* `object` — (optional) the event filter options:

  * `address` — the contract address from which the logs should be fetched. It can be a single address or an array of addresses.

  * `topics` — an array of `DATA` topics. The event topics for which the logs should be fetched. It can be a single topic or an array of topics.

    <Info>
      Read [Tracking some Bored Apes: The Ethereum event logs tutorial](/docs/tracking-some-bored-apes-the-ethereum-event-logs-tutorial) to learn more about topics and event logs.
    </Info>

## Response

* `subscription` — the subscription ID.

* `array` — an array of log objects that match the specified filter:

  * `address` — the contract address from which the event originated.
  * `topics` — an array of 32-byte data fields containing indexed event parameters.
  * `data` — the non-indexed data that was emitted along with the event.
  * `blocknumber` — the block number in which the event was included. `null` if it is pending.
  * `transactionhash` — the hash of the transaction that triggered the event. `null` if pending.
  * `transactionindex` — the integer index of the transaction within the block's list of transactions. `null` if it is pending.
  * `blockhash` — the hash of the block in which the event was included. `null` if it is pending.
  * `logindex` — the integer identifying the index of the event within the block's list of events. `null` if pending.
  * `removed` — the boolean value indicating if the event was removed from the blockchain due to a chain reorganization. `True` if the log was removed. `False` if it is a valid log.

## `eth_subscribe("logs")` code examples

<Info>
  Note that subscriptions require a WebSocket connection and [WebSocket cat](https://www.npmjs.com/package/wscat) for you to use this method in the console.

  Install WebSocket cat with:

  `npm install -g wscat`
</Info>

<CodeGroup>
  ```shell wscat theme={"system"}
  $ wscat -c YOUR_CHAINSTACK_WEBSOCKET_ENDPOINT
  # Wait for the connection to be established

  Connected (press CTRL+C to quit)

  > {"jsonrpc":"2.0","id": 1, "method": "eth_subscribe", "params": ["logs", {"address":"0x82aF49447D8a07e3bd95BD0d56f35241523fBab1","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]}]}
  ```

  ```javascript javascript theme={"system"}
  const WebSocket = require('ws');

  const webSocket = new WebSocket('CHAINSTACK_WSS_URL');

  async function subscribeToNewLogs() {

    const request = {
      id: 1,
      jsonrpc: '2.0',
      method: 'eth_subscribe',
      params: ['logs', {"address":"0x82aF49447D8a07e3bd95BD0d56f35241523fBab1","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]}],
    };

    const onOpen = (event) => {
      webSocket.send(JSON.stringify(request));
    };

    const onMessage = (event) => {
      const response = JSON.parse(event.data);
      console.log(response);
    };

    try {
      webSocket.addEventListener('open', onOpen);
      webSocket.addEventListener('message', onMessage);
    } catch (error) {
      console.error(error);
    }
  }

  subscribeToNewLogs();
  ```
</CodeGroup>

This will generate a continuous stream of data displaying new event logs matching the filter.

Use [eth\_unsubscribe](/reference/gnosis-native-unsubscribe) to remove the subscription.

## Use case

The `eth_subscribe("logs")` method on the Gnosis Chain is used to subscribe to the logs generated by smart contracts on the blockchain. These logs contain information about events that have occurred on the blockchain, such as details of a smart contract function and outputs of transactions.

A practical and real-world scenario for using the `eth_subscribe("logs")` method could be in the context of a decentralized exchange (DEX). In the context of a DEX, trades are executed using smart contracts that run on the Gnosis Chain.

When a trade is executed on a DEX, a smart contract is called to process the transaction. This smart contract generates a log that contains information about the trade, such as the amount of cryptocurrency being traded, the parties involved, and so on.

By using the `eth_subscribe("logs")` method, a user or application can subscribe to the logs generated by the DEX's smart contracts. This can be useful for tracking trades in real time, monitoring the performance of the DEX, and generating reports on trading activity.

For example, a trader might use the `eth_subscribe("logs")` method to monitor the logs generated by a DEX in order to identify trends in trading activity. They might look for patterns in the volume and price of trades, which could help them make more informed trading decisions.

Similarly, an analytics platform might use the `eth_subscribe("logs")` method to collect data on trading activity across multiple DEXs. By analyzing this data, they could generate insights into the performance of different DEXs, which could be useful for investors and traders looking to make informed decisions about where to trade.