> 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/optimism-op/optimism_eth_getunclebyblocknumberandindex.md).

# eth\_getUncleByBlockNumberAndIndex - Optimism

Example code for the eth\_getUncleByBlockNumberAndIndex json-rpc method. Сomplete guide on how to use eth\_getUncleByBlockNumberAndIndex json-rpc in GetBlock.io Web3 documentation.

This method returns uncle block information for a given block number. As with eth\_getUncleByBlockHashAndIndex, this typically returns null on Optimism because the network doesn't have traditional uncles.

### Parameters

| Parameter   | Type            | Description                                       | Required |
| ----------- | --------------- | ------------------------------------------------- | -------- |
| blockNumber | `QUANTITY\|TAG` | Block number in hex, or `'latest'`, `'earliest'`. | Yes      |
| uncleIndex  | `QUANTITY`      | The uncle's index position in hex.                | Yes      |

### Request

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

```bash
curl --location 'https://shared.us-east-1.getblock.io/<ACCESS_TOKEN>' \
--header 'Content-Type: application/json' \
--data '{
   "jsonrpc": "2.0",
   "method": "eth_getUncleByBlockHashAndIndex",
      "params": ["latest", "0x0"],
    "id": "getblock.io"
}'
```

{% endtab %}

{% tab title="Axios" %}

```javascript
import axios from 'axios'
let data = JSON.stringify({
    "jsonrpc": "2.0",
     "method": "eth_getUncleByBlockHashAndIndex",
    "params": ["latest", "0x0"],
    "id": "getblock.io"
};

let config = {
  method: "post",
  maxBodyLength: Infinity,
  url: "https://shared.us-east-1.getblock.io/<ACCESS_TOKEN>",
  headers: {
    "Content-Type": "application/json",
  },
  data: data,
};

axios
  .request(config)
  .then((response) => {
    console.log(JSON.stringify(response.data));
  })
  .catch((error) => {
    console.log(error);
  });

```

{% endtab %}

{% tab title="Request" %}

```python
import requests
import json

url = "https://shared.us-east-1.getblock.io/<ACESS_TOKEN>"

payload = json.dumps({
   "jsonrpc": "2.0",
     "method": "eth_getUncleByBlockHashAndIndex",
    "params": ["latest", "0x0"],
    "id": "getblock.io"
})
headers = {
  'Content-Type': 'application/json'
}

response = requests.request("POST", url, headers=headers, data=payload)

print(response.text)

```

{% endtab %}

{% tab title="Rust" %}

```rs
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = reqwest::Client::builder()
        .build()?;

    let mut headers = reqwest::header::HeaderMap::new();
    headers.insert("Content-Type", "application/json".parse()?);

    let data = r#"{
   "jsonrpc": "2.0",
    "method": "eth_getUncleByBlockHashAndIndex",
    "params": ["latest", "0x0"],
    "id": "getblock.io"
}"#;

    let json: serde_json::Value = serde_json::from_str(&data)?;

    let request = client.request(reqwest::Method::POST, "https://shared.us-east-1.getblock.io/<ACCESS_TOKEN>")
        .headers(headers)
        .json(&json);

    let response = request.send().await?;
    let body = response.text().await?;

    println!("{}", body);

    Ok(())
}
```

{% endtab %}
{% endtabs %}

### Response

A successful response returns the following:

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

### Response Parameters

* **`id`**: A unique request identifier, matching the `id` sent in the request body.
* **`jsonrpc`**: Specifies the use of JSON-RPC version 2.0.
* **`result`**: Uncle block object or null (typically null on Optimism).

### Use Case

The eth\_getUncleByBlockNumberAndIndex method is commonly used for:

* **Ethereum compatibility**
* **API completeness**

### Error handling

| Status Code | Error Message    | Cause                                                      |
| ----------- | ---------------- | ---------------------------------------------------------- |
| 404         | Not Found        | Missing or invalid ACCESS\_TOKEN.                          |
| -32602      | Invalid argument | <ul><li>Invalid block hash</li><li>Invalid index</li></ul> |