> For the complete documentation index, see [llms.txt](https://docs.getblock.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.getblock.io/api-reference/bnb-smart-chain-bsc/eth_subscribe-bsc.md).

# eth\_subscribe - BSC

This method creates a subscription for real-time event notifications on the Celo network. 

{% hint style="info" %}
This requires a WebSocket connection and is ideal for tracking new blocks, pending transactions, or contract events with Celo's fast \~1 second block times.
{% endhint %}

## Parameters

| Parameter        | Type   | Required | Description                                        |
| ---------------- | ------ | -------- | -------------------------------------------------- |
| subscriptionType | string | Yes      | Type: "newHeads", "logs", "newPendingTransactions" |
| options          | object | No       | Filter options (for "logs" type)                   |

## Request Example

{% tabs %}
{% tab title="JavaScript (newHeads)" %}
{% code title="subscribe-newHeads.js" %}

```javascript
const WebSocket = require('ws');

const ws = new WebSocket('wss://go.getblock.io/<ACCESS-TOKEN>/');

ws.on('open', () => {
  ws.send(JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'eth_subscribe',
    params: ['newHeads']
  }));
});

ws.on('message', (data) => {
  console.log(JSON.parse(data));
});
```

{% endcode %}
{% endtab %}

{% tab title="JavaScript (logs - cUSD Transfers)" %}
{% code title="subscribe-logs-cusd.js" %}

```javascript
const WebSocket = require('ws');

const ws = new WebSocket('wss://go.getblock.io/<ACCESS-TOKEN>/');

ws.on('open', () => {
  ws.send(JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'eth_subscribe',
    params: [
      'logs',
      {
        address: '0x765DE816845861e75A25fCA122bb6898B8B1282a',
        topics: ['0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef']
      }
    ]
  }));
});

ws.on('message', (data) => {
  console.log('cUSD Transfer:', JSON.parse(data));
});
```

{% endcode %}
{% endtab %}

{% tab title="Python (websockets)" %}
{% code title="subscribe\_newHeads.py" %}

```python
import asyncio
import websockets
import json

async def subscribe():
    uri = "wss://go.getblock.io/<ACCESS-TOKEN>/"
    async with websockets.connect(uri) as ws:
        await ws.send(json.dumps({
            "jsonrpc": "2.0",
            "id": 1,
            "method": "eth_subscribe",
            "params": ["newHeads"]
        }))
        
        async for message in ws:
            print(json.loads(message))

asyncio.run(subscribe())
```

{% endcode %}
{% endtab %}
{% endtabs %}

## Response Example

{% tabs %}
{% tab title="Result" %}

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x9cef478923ff08bf67fde6c64013158d"
}
```

{% endtab %}

{% tab title="Subscription Notification" %}

```json
{
  "jsonrpc": "2.0",
  "method": "eth_subscription",
  "params": {
    "subscription": "0x9cef478923ff08bf67fde6c64013158d",
    "result": {
      "number": "0x1d9f2a8",
      "hash": "0x4e3a375...",
      "parentHash": "0xb903239...",
      "timestamp": "0x65a1b2c3"
    }
  }
}
```

{% endtab %}
{% endtabs %}

## Response Definition

| Field  | Type   | Description     |
| ------ | ------ | --------------- |
| result | string | Subscription ID |

## Use Cases

* Real-time block notifications
* Live stablecoin transfer tracking
* Pending transaction monitoring
* DeFi event streaming

## Error Handling

| Error Code | Description               |
| ---------- | ------------------------- |
| -32602     | Invalid subscription type |
| -32603     | Internal error            |

## SDK Integration

{% tabs %}
{% tab title="Ethers.js" %}
{% code title="ethers-subscribe.js" %}

```javascript
const { ethers } = require('ethers');

const provider = new ethers.WebSocketProvider('wss://go.getblock.io/<ACCESS-TOKEN>/');

provider.on('block', (blockNumber) => {
  console.log('New block:', blockNumber);
});
```

{% endcode %}
{% endtab %}

{% tab title="Viem" %}
{% code title="viem-watchBlocks.js" %}

```javascript
import { createPublicClient, webSocket } from 'viem';
import { celo } from 'viem/chains';

const client = createPublicClient({
  chain: celo,
  transport: webSocket('wss://go.getblock.io/<ACCESS-TOKEN>/')
});

const unwatch = client.watchBlocks({
  onBlock: block => console.log('Block:', block.number)
});
```

{% endcode %}
{% endtab %}
{% endtabs %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## 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, and the optional `goal` query parameter:

```
GET https://docs.getblock.io/api-reference/bnb-smart-chain-bsc/eth_subscribe-bsc.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

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.