<?php
ini_set('error_reporting', E_ALL);
ini_set('display_errors', true);
$adminJson1 = '{
    "method" : "change_id",
    "data" : {
        "old_id" : "'."0123456789".'",
        "new_id" : "'."9876543210".'"
    }
}';
$postData = $adminJson1;
class PostRequest {
    private $urlApi = "http://abrabr.obr/api.php";
    private $urlAdminApi = "http://abrabr.obr/adminApi.php";
    private $urlLogin = "LoGiN";
    private $urlPassword = "PaSsWoRd";
    function __construct($data){
    $this->sendPostRequest($data);
    }
    function sendPostRequest($data){
        $fields = $data;
        $headers = array(
            'Content-Type: application/json',
            'Authorization: Basic '. base64_encode($this->urlLogin . ":" . $this->urlPassword)
        );
        $fields_string = json_encode($fields);
        $ch = curl_init();
        curl_setopt($ch,CURLOPT_URL, $this->urlAdminApi);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
        curl_setopt($ch, CURLOPT_USERPWD, $this->urlLogin . ":" . $this->urlPassword);
        curl_setopt($ch,CURLOPT_POST, true);
        curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
        curl_setopt($ch,CURLOPT_RETURNTRANSFER, true);
        $result = curl_exec($ch);
        if(curl_errno($ch)){
            throw new Exception(curl_error($ch));
        }
        echo $result;
    }
}
$post = new PostRequest(json_decode($postData, true));

procedure TForm1.SpeedButton1Click(Sender: TObject);
var
    Json: string;
    sResponse: string;
    JsonToSend: TMemoryStream;
    surlAdminApi, surlLogin, surlPassword: string;
begin
    surlAdminApi:= 'http://abrabr.obr/adminApi.php';
    surlLogin:= 'LoGiN';
    surlPassword:= 'PaSsWoRd';
    Json := '{"method" : "change_id","data" : {"old_id" : "0123456789","new_id" : "9876543210"}}';
    memo1.Text := Json;
    try
      JsonToSend := TStringStream.Create(Json, TEncoding.UTF8);
      JsonToSend.Position := 0;
      HTTP1.Request.ContentType := 'application/json';
      HTTP1.Request.CharSet := 'utf-8';
      try
       sResponse := HTTP1.Post(surlAdminApi, JsonToSend);
      except
       on E: Exception do
       ShowMessage('Error: '#13#10 + e.Message);
      end;
    finally
      JsonToSend.Free;
    end;
    memo1.Text := sResponse;
end;