curl --request POST \
  --url https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "eth_getHeaderByNumber",
  "params": [
    "0x34808ff"
  ]
}
'

import requests

url = "https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/"

payload = {
    "id": 1,
    "jsonrpc": "2.0",
    "method": "eth_getHeaderByNumber",
    "params": ["0x34808ff"]
}
headers = {"Content-Type": "application/json"}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({id: 1, jsonrpc: '2.0', method: 'eth_getHeaderByNumber', params: ['0x34808ff']})
};

fetch('https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/', 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://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/",
  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([
    'id' => 1,
    'jsonrpc' => '2.0',
    'method' => 'eth_getHeaderByNumber',
    'params' => [
        '0x34808ff'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($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://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/"

	payload := strings.NewReader("{\n  \"id\": 1,\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"eth_getHeaderByNumber\",\n  \"params\": [\n    \"0x34808ff\"\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))

}

HttpResponse<String> response = Unirest.post("https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/")
  .header("Content-Type", "application/json")
  .body("{\n  \"id\": 1,\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"eth_getHeaderByNumber\",\n  \"params\": [\n    \"0x34808ff\"\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/")

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

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"id\": 1,\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"eth_getHeaderByNumber\",\n  \"params\": [\n    \"0x34808ff\"\n  ]\n}"

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "hash": "0x6dabcf7ed4cf53e05054a4d671b19b7597740bce1042019ff31af68dde9c98a9",
    "parentHash": "0xfe1c06b10e6be606cad7b32b7da87bfba91fc1c45085b7ea12c69070e6cd3778",
    "sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
    "miner": "0xa693cc18aa09d33dd388013b7a02e5ff863b8760",
    "stateRoot": "0xfd095b710adcb8045a8904d02c000f25230b151ef3a4e4b4dbf84ab083c2b9df",
    "transactionsRoot": "0x1df73587a490d0ae7e236905773748ef07ea63c1c22aa93659eb8fd4f77ef04d",
    "receiptsRoot": "0x968419399ee52ee3133e57e9111b513f941f269b5f7e83f358b5b894e8736362",
    "logsBloom": "0x0000000000004000000010200400000040000010002000024080060400000000800000000000002200000000000000000040000402002201000000024000000011000401120800040000000900000200000100002000000100000000800000000000000006000000200a004400004800002000800000000000000010000000c0000000080000000010080000000000c800012001000880000040000000800000000000200240000000008000000000008000000020000000000000000004000004000023001000001008000004000002000000080404084000080110000020600000000000020000000400001002000008200440000100400000000010000000",
    "difficulty": "0x0",
    "number": "0x34808ff",
    "gasLimit": "0x1c9c380",
    "gasUsed": "0x1db35b",
    "timestamp": "0x6a7026be",
    "extraData": "0x00000004a817c800",
    "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "nonce": "0x0000000000000000",
    "baseFeePerGas": "0x4a817c800",
    "withdrawalsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
    "blobGasUsed": "0x0",
    "excessBlobGas": "0x0",
    "parentBeaconBlockRoot": "0xfe1c06b10e6be606cad7b32b7da87bfba91fc1c45085b7ea12c69070e6cd3778",
    "requestsHash": "0xe3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "size": "0xbda"
  }
}