> 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/filecoin-fil/native-api/filecoin_chainhead.md).

# Filecoin.ChainHead - Filecoin

Example code for the Filecoin.ChainHead JSON RPC method. Complete guide on how to use Filecoin.ChainHead JSON RPC in GetBlock Web3 documentation.

This method returns the current head of the chain: the tipset at the latest epoch, including its block CIDs, block headers, and height.

## Parameters

This method does not accept any parameters. Pass an empty array.

## Request

{% tabs %}
{% tab title="cURL" %}
{% code overflow="wrap" %}

```bash
curl --location --request POST 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{"jsonrpc": "2.0", "method": "Filecoin.ChainHead", "params": [], "id": "getblock.io"}'
```

{% endcode %}
{% endtab %}

{% tab title="JavaScript" %}
{% code title="example.js" %}

```javascript
const response = await fetch('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'Filecoin.ChainHead',
        params: [],
        id: 'getblock.io'
    })
});

const data = await response.json();
console.log(data.result);
```

{% endcode %}
{% endtab %}

{% tab title="Python" %}
{% code title="example.py" %}

```python
import requests

response = requests.post(
    'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'Filecoin.ChainHead',
        'params': [],
        'id': 'getblock.io'
    }
)

print(response.json()['result'])
```

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

## Response

```json
{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "Cids": [
            {
                "/": "bafy2bzacecdkonmhngylnnhrk4azkg2wkgcm6cnm5qn5sk4ww5cszjlvkgkd6"
            },
            {
                "/": "bafy2bzaceaglcpzhd5gfrzdyt7ce3e5asnbfz3s3stbqyxniziny5snewbpbg"
            }
        ],
        "Blocks": [
            {
                "Miner": "f01234",
                "Height": 4523891
            }
        ],
        "Height": 4523891
    }
}
```

## Response Parameters

| Field  | Type    | Description                                                      |
| ------ | ------- | ---------------------------------------------------------------- |
| Cids   | array   | CIDs of the blocks in the tipset, each as an object with a / key |
| Blocks | array   | Block headers of the tipset                                      |
| Height | integer | Epoch (block height) of the tipset                               |

## Use Cases

* **Tip Tracking**: Read the current chain height and tipset CIDs
* **Sync Checks**: Compare the head against a local index
* **Polling**: Detect new tipsets by watching the height
* **State Anchoring**: Use the head tipset key for state reads

## Error Handling

| Error Code | Message         | Description                                                 |
| ---------- | --------------- | ----------------------------------------------------------- |
| -32602     | Invalid params  | A parameter is missing or has the wrong type or format      |
| 1          | Actor not found | The address or actor does not exist in the requested tipset |
| -32603     | Internal error  | The node failed to process the request                      |