# submitheader

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

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

Decodes the given hex-encoded block header and submits it as a candidate chain tip if valid. Throws an error if the header is invalid. This can be used to mine on top of a particular block without  having the full block data.


Reference: https://www.alchemy.com/docs/chains/bitcoin/bitcoin-api-endpoints/submitheader

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| hexdata | string | Yes | The hex-encoded block header to submit. |

## Result

**result** (null or string): Returns null if the header was accepted, or a string describing the rejection reason.

## Example

### Request

```json
{
  "jsonrpc": "2.0",
  "method": "submitheader",
  "params": [
    "0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c"
  ],
  "id": 1
}
```

### Response

```json
{
  "jsonrpc": "2.0",
  "result": null,
  "id": 1
}
```

## Code Examples

### cURL

```bash
curl --request POST \
  --url https://bitcoin-mainnet.g.alchemy.com/v2/docs-demo \
  --header 'Content-Type: application/json' \
  --data '{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "submitheader",
  "params": [
    "0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c"
  ]
}'
```

### JavaScript

```javascript
const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'submitheader',
    params: [
      '0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c'
    ]
  })
};

fetch('https://bitcoin-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://bitcoin-mainnet.g.alchemy.com/v2/docs-demo"

payload = {
    "jsonrpc": "2.0",
    "id": 1,
    "method": "submitheader",
    "params": ["0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c"]
}
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://bitcoin-mainnet.g.alchemy.com/v2/docs-demo"

	payload := strings.NewReader("{\n  \"jsonrpc\": \"2.0\",\n  \"id\": 1,\n  \"method\": \"submitheader\",\n  \"params\": [\n    \"0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c\"\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://bitcoin-mainnet.g.alchemy.com/v2/docs-demo")
  .header("Content-Type", "application/json")
  .body("{\n  \"jsonrpc\": \"2.0\",\n  \"id\": 1,\n  \"method\": \"submitheader\",\n  \"params\": [\n    \"0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c\"\n  ]\n}")
  .asString();
```

### C#

```csharp
using RestSharp;


var options = new RestClientOptions("https://bitcoin-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\": \"submitheader\",\n  \"params\": [\n    \"0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c\"\n  ]\n}", false);
var response = await client.PostAsync(request);

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

```


## OpenRPC Method Specification

```yaml
name: submitheader
summary: Decode and submit a block header
description: |
  Decodes the given hex-encoded block header and submits it as a candidate chain tip if valid. Throws an error if the header is invalid. This can be used to mine on top of a particular block without  having the full block data.
params:
  - name: hexdata
    required: true
    description: The hex-encoded block header to submit.
    schema:
      type: string
      pattern: ^[a-fA-F0-9]{160}$
      description: 80-byte (160 hex characters) hex-encoded block header
result:
  name: result
  description: Returns null if the header was accepted, or a string describing the rejection reason.
  schema:
    oneOf:
      - type: 'null'
        description: Header was accepted
      - type: string
        description: Error message if header was rejected
examples:
  - name: submitheader example
    params:
      - name: hexdata
        value: 0000002073bd2184edd74c5c5b4c0c5be04d0e8f5d6b7d5b3b1b1d8e8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c8b8c
    result:
      name: result
      value: null
```