# getblockfilter

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

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

Returns the BIP 157 content filter for a specified block. Requires the blockfilterindex to be enabled.


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

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| blockhash | string | Yes | The hash of the block. |
| filtertype | enum | No | The type name of the filter. Currently only 'basic' is supported. |

## Result

**result** (object): The block filter details.

## Example

### Request

```json
{
  "jsonrpc": "2.0",
  "method": "getblockfilter",
  "params": [
    "00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80",
    "basic"
  ],
  "id": 1
}
```

### Response

```json
{
  "jsonrpc": "2.0",
  "result": {
    "filter": "0180c3b80144ec1762e9eb8e5b2e072f7d8c8c8c0c2c2a2a2a2a2a2a2a2a2a",
    "header": "1e1e1f1f2020202021212121222222222323232324242424252525252626262"
  },
  "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": "getblockfilter",
  "params": [
    "00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80",
    "basic"
  ]
}'
```

### JavaScript

```javascript
const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'getblockfilter',
    params: ['00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80', 'basic']
  })
};

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": "getblockfilter",
    "params": ["00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80", "basic"]
}
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\": \"getblockfilter\",\n  \"params\": [\n    \"00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80\",\n    \"basic\"\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\": \"getblockfilter\",\n  \"params\": [\n    \"00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80\",\n    \"basic\"\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\": \"getblockfilter\",\n  \"params\": [\n    \"00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80\",\n    \"basic\"\n  ]\n}", false);
var response = await client.PostAsync(request);

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

```


## OpenRPC Method Specification

```yaml
name: getblockfilter
summary: Retrieve a BIP 157 content filter for a particular block
description: |
  Returns the BIP 157 content filter for a specified block. Requires the blockfilterindex to be enabled.
params:
  - name: blockhash
    required: true
    description: The hash of the block.
    schema:
      title: Bitcoin Block Hash
      type: string
      pattern: ^[a-fA-F0-9]{64}$
      description: A 64-character hex string representing the block hash.
  - name: filtertype
    required: false
    description: The type name of the filter. Currently only 'basic' is supported.
    schema:
      type: string
      default: basic
      enum:
        - basic
result:
  name: result
  description: The block filter details.
  schema:
    type: object
    properties:
      filter:
        type: string
        description: The hex-encoded filter data.
      header:
        type: string
        description: The hex-encoded filter header.
examples:
  - name: getblockfilter example
    params:
      - name: blockhash
        value: 00000000000000000000669ed57030eb18020ee7029c064f10505156be203d80
      - name: filtertype
        value: basic
    result:
      name: result
      value:
        filter: 0180c3b80144ec1762e9eb8e5b2e072f7d8c8c8c0c2c2a2a2a2a2a2a2a2a2a
        header: 1e1e1f1f2020202021212121222222222323232324242424252525252626262
```