require 'path/to/src/autoload.php';

    $paystack = new Yabacon\Paystack(SECRET_KEY);
    try
    {
      $tranx = $paystack->transaction->initialize([
        'amount'=>$amount,       // in kobo
        'email'=>$email,         // unique to customers
        'reference'=>$reference, // unique to transactions
      ]);
    } catch(\Yabacon\Paystack\Exception\ApiException $e){
      print_r($e->getResponseObject());
      die($e->getMessage());
    }

    // store transaction reference so we can query in case user never comes back
    // perhaps due to network issue
    save_last_transaction_reference($tranx->data->reference);

    // redirect to page so User can pay
    header('Location: ' . $tranx->data->authorization_url);

    // Retrieve the request's body and parse it as JSON
    $event = Yabacon\Paystack\Event::capture();
    http_response_code(200);

    /* It is a important to log all events received. Add code *
     * here to log the signature and body to db or file       */
    openlog('MyPaystackEvents', LOG_CONS | LOG_NDELAY | LOG_PID, LOG_USER | LOG_PERROR);
    syslog(LOG_INFO, $event->raw);
    closelog();

    /* Verify that the signature matches one of your keys*/
    $my_keys = [
                'live'=>'sk_live_blah',
                'test'=>'sk_test_blah',
              ];
    $owner = $event->discoverOwner($my_keys);
    if(!$owner){
        // None of the keys matched the event's signature
        die();
    }

    // Do something with $event->obj
    // Give value to your customer but don't give any output
    // Remember that this is a call from Paystack's servers and
    // Your customer is not seeing the response here at all
    switch($event->obj->event){
        // charge.success
        case 'charge.success':
            if('success' === $event->obj->data->status){
                // TIP: you may still verify the transaction
                // via an API call before giving value.
            }
            break;
    }

    $reference = isset($_GET['reference']) ? $_GET['reference'] : '';
    if(!$reference){
      die('No reference supplied');
    }

    // initiate the Library's Paystack Object
    $paystack = new Yabacon\Paystack(SECRET_KEY);
    try
    {
      // verify using the library
      $tranx = $paystack->transaction->verify([
        'reference'=>$reference, // unique to transactions
      ]);
    } catch(\Yabacon\Paystack\Exception\ApiException $e){
      print_r($e->getResponseObject());
      die($e->getMessage());
    }

    if ('success' === $tranx->data->status) {
      // transaction was successful...
      // please check other things like whether you already gave value for this ref
      // if the email matches the customer who owns the product etc
      // Give value
    }

    $fee = new Yabacon\Paystack\Fee();

    $fee->withPercentage(0.015);        // 1.5%
    $fee->withAdditionalCharge(10000);  // plus 100 NGN
    $fee->withThreshold(250000);        // when total is above 2,500 NGN
    $fee->withCap(200000);              // capped at 2000

    $chargeOn300naira = $fee->calculateFor(30000);
    $chargeOn7000naira = $fee->calculateFor(700000);

    $iWant100Naira = $fee->addFor(10000);
    $iWant4000Naira = $fee->addFor(400000);

    $event = Yabacon\Paystack\Event::capture();

    if($event->validFor($mySecretKey))
    {
        // awesome
    }

    $my_keys = [
                'live'=>'sk_live_blah',
                'test'=>'sk_test_blah',
              ];
    $owner = $event->discoverOwner($my_keys);
    if(!$owner){
        // None of my keys matched the event's signature
        die();
    }

    $evt->forwardTo('http://another-webhook.url');

    $builder = new MetadataBuilder();

    $builder->withQuoteId(10); // will add as quote_id: 10 unless you turn auto_snake_case off
    $builder->withMobileNumber(08012345678); // will add as mobile_number: 08012345678
    $builder->withCSRF('dontacceptpaymentunlessthismatches');

    MetadataBuilder::$auto_snake_case = false;

    $builder->withCustomField('Mobile Number', '080123456789');
    $builder->withCustomField('See Me', 'I\'m Visible on your Dashboard');

    $paystack = new Yabacon\Paystack(SECRET_KEY);
    $paystack->useRoutes(["charge" => Charge::class]);

    $paystack->charge->chargeMobileMoney([
          'email' => 'hey@example.com',
          'reference' => 'trnx_ref',
          'amount' => 50 * 100,
          'currency' => 'GHS',
          'mobile_money' => [
            'phone' => '5533467',
            'provider' => 'MTN'
          ]
    ]);

    class Charge implements RouteInterface
    {

        public static function root()
        {
            return '/charge';
        }

        public static function chargeMobileMoney()
        {
            return [
                RouteInterface::METHOD_KEY => RouteInterface::POST_METHOD,
                RouteInterface::ENDPOINT_KEY => Charge::root(),
                RouteInterface::PARAMS_KEY => [
                    'email',
                    'reference',
                    'amount',
                    'currency',
                    'mobile_money',
                ],
            ];
        }
    }