# chain_getHeader

> For the complete documentation index, see [llms.txt](/docs/llms.txt).

POST https://astar-mainnet.g.alchemy.com/v2/{apiKey}

Returns the header of the block identified by the given hash. If no hash is provided, returns the header of the best (latest) block.

Reference: https://www.alchemy.com/docs/chains/astar/astar-api-endpoints/chain-get-header

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| hash | string | No | The block hash to retrieve the header for. If omitted, returns the header of the current best block. |

## Result

**Header** (object): The block header object containing metadata about the block.

## Code Examples

### cURL

```bash
curl --request POST \
  --url https://astar-mainnet.g.alchemy.com/v2/docs-demo \
  --header 'Content-Type: application/json' \
  --data '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "chain_getHeader",
  "params": [
    "string"
  ]
}'
```

### JavaScript

```javascript
const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({jsonrpc: '2.0', id: 1, method: 'chain_getHeader', params: ['string']})
};

fetch('https://astar-mainnet.g.alchemy.com/v2/docs-demo', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));
```

### Python

```python
import requests

url = "https://astar-mainnet.g.alchemy.com/v2/docs-demo"

payload = {
    "jsonrpc": "2.0",
    "id": 1,
    "method": "chain_getHeader",
    "params": ["string"]
}
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.text)
```

### Go

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://astar-mainnet.g.alchemy.com/v2/docs-demo"

	payload := strings.NewReader("{\n  \"jsonrpc\": \"2.0\",\n  \"id\": 1,\n  \"method\": \"chain_getHeader\",\n  \"params\": [\n    \"string\"\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}
```

### Java

```java
HttpResponse<String> response = Unirest.post("https://astar-mainnet.g.alchemy.com/v2/docs-demo")
  .header("Content-Type", "application/json")
  .body("{\n  \"jsonrpc\": \"2.0\",\n  \"id\": 1,\n  \"method\": \"chain_getHeader\",\n  \"params\": [\n    \"string\"\n  ]\n}")
  .asString();
```

### C#

```csharp
using RestSharp;


var options = new RestClientOptions("https://astar-mainnet.g.alchemy.com/v2/docs-demo");
var client = new RestClient(options);
var request = new RestRequest("");
request.AddJsonBody("{\n  \"jsonrpc\": \"2.0\",\n  \"id\": 1,\n  \"method\": \"chain_getHeader\",\n  \"params\": [\n    \"string\"\n  ]\n}", false);
var response = await client.PostAsync(request);

Console.WriteLine("{0}", response.Content);

```


## OpenRPC Method Specification

```yaml
name: chain_getHeader
summary: Retrieves the header for a specific block
description: Returns the header of the block identified by the given hash. If no hash is provided, returns the header of the best (latest) block.
x-compute-units: 10
params:
  - name: hash
    required: false
    description: The block hash to retrieve the header for. If omitted, returns the header of the current best block.
    schema:
      type: string
result:
  name: Header
  description: The block header object containing metadata about the block.
  schema:
    type: object
    example:
      parentHash: '0xf0b30ecdc94c481ca96237d2a17408fef6c401f705a1f5f911e58d2a1f33fcb6'
      number: '0x14fd'
      stateRoot: '0xaa796217f92ed5a40ec03d184b05ad1e1824d2824559719b9bef3304ee3bff55'
      extrinsicsRoot: '0x82faad984718975bccbfd58fdc67f59d367d678419a918f79c7a58cbb8e34a5b'
      digest:
        logs:
          - 0x0642414245b50101000000...
          - 0x054241424501011687815...
    properties:
      parentHash:
        type: string
      number:
        type: string
      stateRoot:
        type: string
      extrinsicsRoot:
        type: string
      digest:
        type: object
        properties:
          logs:
            type: array
            items:
              type: string
```