curl --request POST \
  --url https://api.kas.fyi/v1/rpc/getBlockTemplate \
  --header 'Content-Type: application/json' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "payAddress": "kaspa:qpzpfwcsqsxhxwup26r55fd0ghqlhyugz8cp6y3wxuddc02vcxtjg75pspnwz",
  "extraData": "Extra block data"
}
'

import requests

url = "https://api.kas.fyi/v1/rpc/getBlockTemplate"

payload = {
    "payAddress": "kaspa:qpzpfwcsqsxhxwup26r55fd0ghqlhyugz8cp6y3wxuddc02vcxtjg75pspnwz",
    "extraData": "Extra block data"
}
headers = {
    "x-api-key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'x-api-key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    payAddress: 'kaspa:qpzpfwcsqsxhxwup26r55fd0ghqlhyugz8cp6y3wxuddc02vcxtjg75pspnwz',
    extraData: 'Extra block data'
  })
};

fetch('https://api.kas.fyi/v1/rpc/getBlockTemplate', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.kas.fyi/v1/rpc/getBlockTemplate",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'payAddress' => 'kaspa:qpzpfwcsqsxhxwup26r55fd0ghqlhyugz8cp6y3wxuddc02vcxtjg75pspnwz',
    'extraData' => 'Extra block data'
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json",
    "x-api-key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

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

func main() {

	url := "https://api.kas.fyi/v1/rpc/getBlockTemplate"

	payload := strings.NewReader("{\n  \"payAddress\": \"kaspa:qpzpfwcsqsxhxwup26r55fd0ghqlhyugz8cp6y3wxuddc02vcxtjg75pspnwz\",\n  \"extraData\": \"Extra block data\"\n}")

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

	req.Header.Add("x-api-key", "<api-key>")
	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))

}

HttpResponse<String> response = Unirest.post("https://api.kas.fyi/v1/rpc/getBlockTemplate")
  .header("x-api-key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"payAddress\": \"kaspa:qpzpfwcsqsxhxwup26r55fd0ghqlhyugz8cp6y3wxuddc02vcxtjg75pspnwz\",\n  \"extraData\": \"Extra block data\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.kas.fyi/v1/rpc/getBlockTemplate")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["x-api-key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"payAddress\": \"kaspa:qpzpfwcsqsxhxwup26r55fd0ghqlhyugz8cp6y3wxuddc02vcxtjg75pspnwz\",\n  \"extraData\": \"Extra block data\"\n}"

response = http.request(request)
puts response.read_body

{
  "block": {
    "header": {
      "version": 1,
      "parentsByLevel": [
        [
          "0x1234567890abcdef..."
        ],
        [
          "0x9876543210fedcba..."
        ]
      ],
      "hashMerkleRoot": "34e9538fd3225652553930657c3d767d5ccab0fcd545038a69c202e45929dcd6",
      "acceptedIdMerkleRoot": "34e9538fd3225652553930657c3d767d5ccab0fcd545038a69c202e45929dcd6",
      "utxoCommitment": "34e9538fd3225652553930657c3d767d5ccab0fcd545038a69c202e45929dcd6",
      "timestamp": "1638360000000",
      "bits": 393216,
      "nonce": "12345678901234567890",
      "daaScore": "1234567",
      "blueWork": "123456789012345",
      "blueScore": "1234567",
      "pruningPoint": "34e9538fd3225652553930657c3d767d5ccab0fcd545038a69c202e45929dcd6"
    },
    "transactions": [
      {
        "version": 0,
        "inputs": [
          {
            "previousOutpoint": {
              "transactionId": "fa99f98b8e9b0758100d181eccb35a4c053b8265eccb5a89aadd794e087d9820",
              "index": 1
            },
            "signatureScript": "4123c94e322fd98ce4ba8b2e33b47f2984a2f741ecfea6fb48eb90d209a46b9d58639888a1575a717cb243b006edd720a7153e9a7e63f4539958d0a44eea8bfa9f01",
            "sequence": 0,
            "sigOpCount": 1
          }
        ],
        "outputs": [
          {
            "value": "100000",
            "scriptPublicKey": {
              "version": 0,
              "script": "208b42bec57f9a538f740b067f947a5b29e04043218a37ff1fa7fb5ee850fd3fd3ac"
            }
          }
        ],
        "lockTime": 0,
        "subnetworkId": "0000000000000000000000000000000000000000",
        "gas": "0",
        "payload": ""
      }
    ]
  }
}