> 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/robinhood/eth_subscribe-robinhood.md).

# eth\_subscribe - Robinhood

Subscribes to events over WebSocket. Returns a subscription ID; matching events arrive as separate WebSocket messages with that ID. Supported subscription types: `newHeads` (new block headers), `logs` (filtered event logs), `newPendingTransactions` (pending tx hashes), `syncing` (sync status changes). With Robinhood Chain's 100ms block cadence, `newHeads` fires very frequently — ensure your consumer can handle the throughput.

{% hint style="warning" %}
**WebSocket-only method.**
{% endhint %}

## Parameters

| Parameter | Type   | Required | Description                                                                        |
| --------- | ------ | -------- | ---------------------------------------------------------------------------------- |
| type      | string | Yes      | Subscription type — one of `newHeads`, `logs`, `newPendingTransactions`, `syncing` |
| filter    | object | No       | For `logs` subscriptions: filter object with `address` and `topics`                |

## Request Example

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

```bash
# WebSocket-only method. Use wscat (or similar) to connect first:
wscat -c 'wss://shared.us-east-1.getblock.io/<ACCESS-TOKEN>/'

# Then send:
{"jsonrpc": "2.0", "method": "eth_subscribe", "params": ["newHeads"], "id": "getblock.io"}
```

{% endtab %}

{% tab title="JavaScript (Axios)" %}

```javascript
import WebSocket from 'ws';

const ws = new WebSocket('wss://shared.us-east-1.getblock.io/<ACCESS-TOKEN>/');

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

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

{% endtab %}

{% tab title="Python (Requests)" %}

```python
import asyncio
import json
import websockets

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

asyncio.run(main())
```

{% endtab %}

{% tab title="Rust (Reqwest)" %}

```rust
use tokio_tungstenite::connect_async;
use tokio_tungstenite::tungstenite::Message;
use serde_json::json;
use futures_util::{SinkExt, StreamExt};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let (mut ws_stream, _) = connect_async("wss://shared.us-east-1.getblock.io/<ACCESS-TOKEN>/").await?;

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "eth_subscribe",
        "params": [
                "newHeads"
        ],
        "id": "getblock.io"
});
    ws_stream.send(Message::Text(payload.to_string())).await?;

    while let Some(msg) = ws_stream.next().await {
        println!("{:?}", msg?);
    }
    Ok(())
}
```

{% endtab %}
{% endtabs %}

## Response Example

{% code overflow="wrap" %}

```json
{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "0xcd0c3e8af590364c09d0fa6a1210faf5"
}
```

{% endcode %}

## Response Parameters

| Field  | Type   | Description                                                                              |
| ------ | ------ | ---------------------------------------------------------------------------------------- |
| result | string | Subscription ID — match incoming notifications by this and use to call `eth_unsubscribe` |

## Use Cases

* Real-time block notifications for indexers and explorers
* Live Stock Token transfer tracking (subscribe to `logs` filtered to Stock Token contracts)
* Mempool monitoring (`newPendingTransactions`)
* Detecting sync state changes

## Error Handling

| Status Code | Error Message             | Cause                                           |
| ----------- | ------------------------- | ----------------------------------------------- |
| 403         | Forbidden                 | Missing or invalid `<ACCESS-TOKEN>`             |
| -32602      | Invalid params            | Request parameters are missing or malformed     |
| -32603      | Internal error            | Server-side error while processing the request  |
| 429         | Too Many Requests         | Rate limit exceeded for your plan               |
| -32600      | Invalid Request           | `eth_subscribe` called over HTTP; use WebSocket |
| -32602      | Invalid subscription type | Type is not one of the four supported           |

## SDK Integration

{% tabs %}
{% tab title="ethers.js" %}
{% code overflow="wrap" %}

```javascript
import { ethers } from 'ethers';

const provider = new ethers.WebSocketProvider('wss://shared.us-east-1.getblock.io/<ACCESS-TOKEN>/');

// For 'newHeads' subscription:
provider.on('block', (blockNumber) => {
    console.log('New block:', blockNumber);
});

// For 'logs' subscription with a filter:
// provider.on({ address: '0x...', topics: [...] }, (log) => { ... });
```

{% endcode %}
{% endtab %}

{% tab title="viem" %}

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

const client = createPublicClient({
    transport: webSocket('wss://shared.us-east-1.getblock.io/<ACCESS-TOKEN>/')
});

// Subscribe to new blocks:
const unwatch = client.watchBlocks({
    onBlock: block => console.log('New block:', block.number)
});
// Call unwatch() when done.
```

{% endtab %}
{% endtabs %}