> 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/nervos-ckb/get_tip_header-nervos.md).

# get\_tip\_header - Nervos

Example code for the get\_tip\_header JSON-RPC method. Complete guide on how to use get\_tip\_header JSON-RPC in GetBlock Web3 documentation.

Returns the header of the tip block in the canonical chain. This is the cheapest way to check the current chain tip and confirm node liveness.

## Parameters

* None

## Request Example

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

```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": "get_tip_header",
    "params": [],
    "id": "getblock.io"
}'
```

{% endtab %}

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

```javascript
import axios from 'axios';

const data = JSON.stringify({
    "jsonrpc": "2.0",
    "method": "get_tip_header",
    "params": [],
    "id": "getblock.io"
});

const config = {
    method: 'post',
    url: 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers: {
        'Content-Type': 'application/json'
    },
    data: data
};

axios(config)
    .then(response => console.log(JSON.stringify(response.data, null, 2)))
    .catch(error => console.log(error));
```

{% endtab %}

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

```python
import requests
import json

url = "https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/"

payload = json.dumps({
    "jsonrpc": "2.0",
    "method": "get_tip_header",
    "params": [],
    "id": "getblock.io"
})

headers = {
    'Content-Type': 'application/json'
}

response = requests.post(url, headers=headers, data=payload)
print(response.text)
```

{% endtab %}

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

```rust
use reqwest::Client;
use serde_json::json;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "get_tip_header",
        "params": [],
        "id": "getblock.io"
});

    let response = client
        .post("https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);

    Ok(())
}
```

{% endtab %}
{% endtabs %}

## Response Example

{% code overflow="wrap" %}

```json
{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "compact_target": "0x1a08a97e",
        "dao": "0x40e8ea22a06a82822f9000c0d77b14002c5f3a0d4f8e4b07009fbd9f4d1f3909",
        "epoch": "0x707080a000ca6",
        "extra_hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "hash": "0x02530b25ad0ff677acc365cb73de3e8cc09c7ddd58272e879252e199d08df83b",
        "nonce": "0x37b54e3aef60b89321e7e8b3ce0f4c2d",
        "number": "0xe5a45f",
        "parent_hash": "0x77fdd22f6ae8a717de9ae2b128834e9b2a1bb7e7387f01ddc278c6ec37ebaa05",
        "proposals_hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
        "timestamp": "0x18f3b8d2a3c",
        "transactions_root": "0x6a7e8d3f1c4b9a2e5d8b7c4f9a3e6b1d5c8a2f4e7b1d6c9a3e5b8d2f4a6c8e0b",
        "version": "0x0"
    }
}
```

{% endcode %}

## Response Parameters

| Field                     | Type                    | Description                                                                    |
| ------------------------- | ----------------------- | ------------------------------------------------------------------------------ |
| result.hash               | H256                    | Hash of the tip block (32 bytes hex)                                           |
| result.number             | Uint64                  | Block number in hex                                                            |
| result.parent\_hash       | H256                    | Hash of the parent block                                                       |
| result.timestamp          | Uint64                  | Unix timestamp in milliseconds (hex)                                           |
| result.epoch              | EpochNumberWithFraction | Packed epoch number, index, length                                             |
| result.compact\_target    | Uint32                  | PoW difficulty target in compact form                                          |
| result.dao                | Byte32                  | Hash containing DAO-related fields (occupied capacity, accumulated rate, etc.) |
| result.nonce              | Uint128                 | PoW nonce found by the miner                                                   |
| result.transactions\_root | H256                    | Root of the Merkle tree of transactions                                        |
| result.version            | Uint32                  | Block version                                                                  |

## Use Cases

* Polling for new tip blocks in indexers
* Light health checks before routing reads
* Tracking chain progression in monitoring dashboards

## Error Handling

| Status Code | Error Message     | Cause                                                |
| ----------- | ----------------- | ---------------------------------------------------- |
| 403         | Forbidden         | Missing or invalid `<ACCESS-TOKEN>`                  |
| -32602      | Invalid params    | Request parameters are missing or malformed          |
| -32601      | Method not found  | Method does not exist or is not enabled on this node |
| -32603      | Internal error    | Server-side error while processing the request       |
| 429         | Too Many Requests | Rate limit exceeded for your plan                    |

## SDK Integration

{% tabs %}
{% tab title="@ckb-lumos/lumos" %}

```javascript
import { RPC } from '@ckb-lumos/rpc';

const rpc = new RPC('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/');

// Lumos provides typed methods on `rpc` (e.g. rpc.getTipHeader(), rpc.getBlock(hash)).
// For raw access to any CKB RPC method:
const result = await rpc.send('get_tip_header', []);
console.log(result);
```

{% endtab %}

{% tab title="ckb-sdk-python / requests" %}

```python
# Using the official CKB SDK Python (ckb-sdk-python).
# For methods not yet wrapped, fall back to raw requests.
import requests

response = requests.post('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', json={
    'jsonrpc': '2.0',
    'id': 'getblock.io',
    'method': 'get_tip_header',
    'params': []
}})
print(response.json())
```

{% endtab %}
{% endtabs %}