SagePay API - Incorrect request format when creating a transaction - Php

The JSON string being sent in the POST body is not valid JSON.

There is an illegal trailing comma after "save": "false",.

A much better way to formulate your request would be something like this:

$postArray = [  'transactionType' => 'Payment',  'paymentMethod' => [    'card' => [      'merchantSessionKey' => '1234',      'cardIdentifier' => '555',      'save' => 'false',    ],  ],  'vendorTxCode' => 'demotransaction1529515635',  'amount' => 10000,  'currency' => 'GBP',  'description' => 'Demo transaction',  'apply3DSecure' => 'UseMSPSetting',  'customerFirstName' => 'Sam',  'customerLastName' => 'Jones',  'billingAddress' => [    'address1' => '407 St. John Street',    'city' => 'London',    'postalCode' => 'EC1V 4AB',    'country' => 'GB',  ],  'entryMethod' => 'Ecommerce',];$postBody = json_encode($postArray);curl_setopt_array($curl, array(        CURLOPT_URL => "https://pi-test.sagepay.com/api/v1/transactions",        CURLOPT_RETURNTRANSFER => true,        CURLOPT_POST => 1,        CURLOPT_POSTFIELDS => $postBody,        CURLOPT_HTTPHEADER => array(            "Authorization: Basic xyz=",            "Cache-Control: no-cache",            "Content-Type: application/json"        ),    ));

Setting up the data as an array and then sending it through json_encode() makes it much easier to modify and change. That will also handle proper encoding of any special characters.