Automating Scheduled Payments with Paystack API in PHP

Managing scheduled payments manually can be tedious and prone to errors, especially when dealing with multiple recipients. Automating this process with the Paystack API simplifies the workflow, ensuring that payments are processed quickly and securely. In this guide, we will walk through how to create a PHP script that interacts with the Paystack API to automate scheduled payments.

We'll cover everything from retrieving payment details from a database to creating Paystack transfer recipients and finally processing payments. Additionally, we’ll update our database to reflect the status of each transaction.

Prerequisites

Paystack Account: You will need a Paystack account with access to their API keys. Sign up at Paystack.
PHP: Make sure PHP is installed on your server.
MySQL: A MySQL database will be used to store the payout details.
cURL: Your server must support cURL, as it is required to send HTTP requests to the Paystack API.

Paystack API Endpoints

Transfer Recipient Endpoint: This is used to create a recipient profile in Paystack.
- URL: https://api.paystack.co/transferrecipient
Transfer Endpoint: This is used to initiate a transfer to a previously created recipient.
- URL: https://api.paystack.co/transfer

Step 1: Database Structure

We will use a MySQL table paystackpayout to store the payment details, including the status of the transaction. The basic structure of the table is as follows:

CREATE TABLE `paystackpayout` (
    `id` INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `email` VARCHAR(100) NOT NULL,
    `fullname` VARCHAR(255) NOT NULL,
    `reference` VARCHAR(50) NOT NULL UNIQUE,
    `amount` DECIMAL(10,2) NOT NULL,
    `bankCode` VARCHAR(10) NOT NULL,
    `accountNumber` VARCHAR(10) NOT NULL,
    `status8` TINYINT(1) DEFAULT 0,
    `status` VARCHAR(50) DEFAULT 'Pending'
);

status8: This column will be set to 0 for unpaid transactions and updated to 1 once a payment is successful.
reference: Each transaction will have a unique reference to ensure no duplicate payments.

Step 2: PHP Script to Automate Payments

Including Configuration File

In your script, you need to include the configuration file where the database connection ($link) is established:

include("config.php");

Fetching Pending Payments

We'll select records where status8 = 0, indicating that the payment is yet to be made.

$sql = "SELECT email, fullname, reference, amount, bankCode, accountNumber FROM paystackpayout WHERE status8 = 0";
$result = mysqli_query($link, $sql);

Creating Paystack Transfer Recipients

For each recipient, we need to create a transfer recipient using Paystack’s API. This requires the recipient’s name, account number, and bank code.

$url = "https://api.paystack.co/transferrecipient";
$authorization = "Authorization: Bearer your_secret_key";  // Replace with your secret key
$data = json_encode([
    "type" => "nuban",
    "name" => $fullname,
    "account_number" => $accountNumber,
    "bank_code" => $bankCode,
    "currency" => "NGN"
]);

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    "Content-Type: application/json",
    $authorization
]);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$response = curl_exec($ch);
$responseData = json_decode($response, true);
curl_close($ch);

if ($responseData['status']) {
    $recipient_code = $responseData['data']['recipient_code'];
} else {
    echo "Error creating transfer recipient: " . $responseData['message'];
    continue;
}

If successful, the recipient’s code will be used in the next step to initiate a transfer.

Initiating the Transfer

After successfully creating a recipient, we can now make the transfer using Paystack’s transfer API.

$url = "https://api.paystack.co/transfer";
$data = json_encode([
    "source" => "balance",
    "reason" => "Withdrawal",
    "amount" => intval($amount * 100),  // Convert the amount to kobo
    "recipient" => $recipient_code
]);

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    "Content-Type: application/json",
    $authorization
]);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$response = curl_exec($ch);
$responseData = json_decode($response, true);
curl_close($ch);

if ($responseData['status']) {
    $transfer_code = $responseData['data']['transfer_code'];
    echo "Transfer successful for reference $reference. Transfer Code: $transfer_code<br>";
} else {
    echo "Error initiating transfer: " . $responseData['message'];
    continue;
}

Updating the Payment Status

If the transfer is successful, we update the status8 field to 1 and the status to 'Success' in the database.

$updateSql = "UPDATE paystackpayout SET status='Success', status8=1 WHERE reference='$reference'";
mysqli_query($link, $updateSql);

Complete Script

Here’s the complete script that ties everything together:

<?php

include("config.php");

// Fetch records from paystackpayout where status8=0
$sql = "SELECT email, fullname, reference, amount, bankCode, accountNumber FROM paystackpayout WHERE status8 = 0";
$result = mysqli_query($link, $sql);

if (mysqli_num_rows($result) > 0) {
    while ($row = mysqli_fetch_assoc($result)) {
        $email = $row['email'];
        $fullname = $row['fullname'];
        $reference = $row['reference'];
        $amount = $row['amount'];
        $bankCode = $row['bankCode'];
        $accountNumber = $row['accountNumber'];

        // Create Transfer Recipient
        $url = "https://api.paystack.co/transferrecipient";
        $authorization = "Authorization: Bearer your_secret_key";
        $data = json_encode([
            "type" => "nuban",
            "name" => $fullname,
            "account_number" => $accountNumber,
            "bank_code" => $bankCode,
            "currency" => "NGN"
        ]);

        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            "Content-Type: application/json",
            $authorization
        ]);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

        $response = curl_exec($ch);
        $responseData = json_decode($response, true);
        curl_close($ch);

        if ($responseData['status']) {
            $recipient_code = $responseData['data']['recipient_code'];

            // Initiate Transfer
            $url = "https://api.paystack.co/transfer";
            $data = json_encode([
                "source" => "balance",
                "reason" => "Withdrawal",
                "amount" => intval($amount * 100),
                "recipient" => $recipient_code
            ]);

            $ch = curl_init($url);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($ch, CURLOPT_HTTPHEADER, [
                "Content-Type: application/json",
                $authorization
            ]);
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

            $response = curl_exec($ch);
            $responseData = json_decode($response, true);
            curl_close($ch);

            if ($responseData['status']) {
                $transfer_code = $responseData['data']['transfer_code'];
                echo "Transfer successful for reference $reference. Transfer Code: $transfer_code<br>";

                // Update status8 to 1 in paystackpayout
                $updateSql = "UPDATE paystackpayout SET status='Success', status8=1 WHERE reference='$reference'";
                mysqli_query($link, $updateSql);
            } else {
                echo "Error initiating transfer for reference $reference: " . $responseData['message'];
            }
        } else {
            echo "Error creating transfer recipient for reference $reference: " . $responseData['message'];
        }
    }
} else {
    echo "No pending payments found.";
}

?>

Step 3: Testing

Ensure that you have filled in your Paystack secret key where appropriate.
Populate the paystackpayout table with test data.
Run the script and monitor the output for successful transfers.
Check the Paystack dashboard to verify the transfers.

Conclusion

By automating your payment process with Paystack's API, you can eliminate the need for manual intervention, reduce errors, and streamline your payment workflow. This script fetches payment details, creates transfer recipients, initiates transfers, and updates your database accordingly, ensuring a smooth

and automated payment process.