curl --request POST \
  --url https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "eth_getTransactionByBlockHashAndIndex",
  "params": [
    "0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc",
    "0x0"
  ]
}
'

import requests

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

payload = {
    "id": 1,
    "jsonrpc": "2.0",
    "method": "eth_getTransactionByBlockHashAndIndex",
    "params": ["0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc", "0x0"]
}
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_getTransactionByBlockHashAndIndex',
    params: ['0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc', '0x0']
  })
};

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_getTransactionByBlockHashAndIndex',
    'params' => [
        '0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc',
        '0x0'
    ]
  ]),
  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_getTransactionByBlockHashAndIndex\",\n  \"params\": [\n    \"0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc\",\n    \"0x0\"\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_getTransactionByBlockHashAndIndex\",\n  \"params\": [\n    \"0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc\",\n    \"0x0\"\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_getTransactionByBlockHashAndIndex\",\n  \"params\": [\n    \"0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc\",\n    \"0x0\"\n  ]\n}"

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

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "type": "0x0",
    "chainId": "0x4cef52",
    "nonce": "0x4",
    "gasPrice": "0x53724e000",
    "gas": "0x927c0",
    "to": "0xd011948bd0d6d433d4ba6df9dc44eb9a2bfa555f",
    "value": "0x0",
    "input": "0xb61d27f60000000000000000000000001ff9c167b50d05910ffdadb82d3d2da4508330ca0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000006000000000000000000000000000000000000000000000000000000000000000040a617bee00000000000000000000000000000000000000000000000000000000",
    "r": "0x90ad8b5cd38ec2759cba501be2e953c738142f535800f8c1e9e25a97fec1a7d3",
    "s": "0x78c101e63dba589c48042e38bc3a458d2e4a01d0285a0ede2e114a9c690a3ebd",
    "v": "0x99dec7",
    "hash": "0xfc48f7c70e8ffaa46b1110dc43f32e90f65434a0949edab384d066c820c57ee2",
    "blockHash": "0xa86891cc8ae2e3efe67b21e24f8f852e76a0875892e9e8c9a4c77aab8e2761cc",
    "blockNumber": "0x3480c62",
    "transactionIndex": "0x0",
    "from": "0x19d7cf8ea0ce468417d1eda365a222a9dcbc7d27"
  }
}