Choosing a payment gateway for your online store

Why Choosing a Payment Gateway Is a Critical Decision for Your Store?

When it comes to launching or growing an online store, many business owners first think about website design, sourcing products, and marketing. But the payment gateway is the exact point the customer encounters at the moment of deciding to buy. If this step is not simple, fast, and reliable, even the best product and most attractive ad won't lead to a sale. Choosing the right payment gateway directly affects your cart conversion rate, business cash flow, and customer trust.

In this article, instead of merely introducing companies, we'll look at the technical and operational criteria you should examine before signing a contract with any provider. Fees, settlement time, payment experience, and technical integration requirements are the four main pillars of this decision.

Transaction Fees; a Cost Overlooked in Pricing

Many stores treat the payment gateway fee as a small, fixed cost when calculating profitability. But when transaction volume rises, this number quickly becomes a significant figure. Fees are usually charged in two ways: a percentage of the transaction amount and a flat fee per transaction.

Fee Structure Across Different Gateways

In Iran, payment gateway fees typically range from 1% to 2% of the transaction amount. Some providers also add a flat fee (e.g., 200 to 500 Toman) for small transactions. For a store with an average order value of 500,000 Toman, the difference between a 1% and 2% fee means 5,000 Toman per sale. If you have 1,000 transactions per month, that difference becomes 5 million Toman monthly.

Another important point is the fee for failed transactions. Some gateways charge a fee even for transactions that fail for any reason (customer cancellation, bank error, insufficient funds). Be sure to ask about this clearly before signing the contract and include it in your monthly cost calculations.

Settlement Time; Your Cash Flow Depends on This Number

Settlement refers to the process of transferring funds from the gateway's intermediary account to the seller's bank account. This time varies from 24 hours to 7 business days across different payment gateways. For a new store that needs to restock inventory, a delay in settlement can mean losing sales opportunities.

Instant Settlement vs. Periodic Settlement

Some gateways offer instant settlement (for a higher fee). This option is critical for stores facing severe cash flow fluctuations or operating during peak sales periods (such as Nowruz or Black Friday-like sales). However, for stable businesses with regular cash flow, 48-hour settlement is usually sufficient and costs less.

Be sure to look for clauses in the contract that specify the maximum settlement time. Some gateways state "up to 7 business days" in the contract but actually settle within 24 hours. Conversely, others may use the maximum allowed time under certain conditions (such as bank holidays). For financial planning, always consider the worst-case scenario.

Payment Experience; Where the Customer Makes the Final Decision

Every extra step in the payment process causes a percentage of customers to abandon their purchase. Global statistics show that for every second of delay in loading the payment page, the conversion rate drops by about 7%. In Iran, this sensitivity is even more complex due to the variety of payment methods and different user habits.

On-Page Payment vs. Redirect

Payment gateways work in two main ways: redirect-based, which takes the customer to the bank's or PSP's payment page, and direct (on-page), where the payment form is displayed on the store's own page. Direct gateways usually have higher conversion rates but require stricter security compliance (such as SSL and PCI DSS).

In addition to the connection type, pay attention to these aspects of the payment experience:

• Support for all bank cards: Some gateways only work with the Shetab network, while others also support credit cards and digital wallets.
• Responsive payment page: Over 60% of Iranian online store traffic comes from mobile. If the payment page doesn't display properly on mobile, you'll lose the customer.
• Guest checkout: Forcing registration before payment is one of the biggest causes of customer drop-off. Your payment gateway should allow payment without registration.
• Automatic return to the store: After a successful or failed payment, the customer should be automatically redirected to the result page on your store, not left stranded on the bank's page.

Technical Integration Requirements; From API to Webhooks

Before choosing a payment gateway, you need to ensure that your technical team (or the developer you hire) can easily integrate it with your store. This becomes especially important when you're using ready-made e-commerce platforms like WooCommerce, Shopify, or custom systems.

Documentation and Ready-Made Libraries

A good payment gateway should have complete and up-to-date API documentation. The technical minimums you should check include:

• Availability of an SDK or official library for your programming language (PHP, Python, Node.js, etc.)
• Webhook support for automatically notifying your server of transaction results
• Persian documentation and real code examples (not just theoretical samples)
• A sandbox/test environment where you can simulate the payment process without real money

For example, if you're using WooCommerce, the gateway's official plugin should be regularly updated and compatible with the latest versions of WooCommerce and WordPress. Outdated plugins that haven't been updated for months usually face security issues and incompatibilities.

Simple Integration Code Sample

Suppose you want to manually integrate a payment gateway into a simple PHP form. The request structure typically looks like this:

// Create transaction request
$data = [
    'merchant_id' => 'YOUR_MERCHANT_ID',
    'amount' => 250000,
    'callback_url' => 'https://yourstore.com/payment/verify',
    'description' => 'Order #1234'
];

$ch = curl_init('https://api.gateway.com/v1/payment');
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Content-Type: application/json',
    'Accept: application/json'
]);
$response = curl_exec($ch);
$result = json_decode($response, true);
// Redirect the customer to $result['payment_url']

This is just a simple example. In practice, you also need to calculate the digital signature of requests, which is usually created by combining the API key and the transaction amount. Be sure to read the exact documentation of the gateway you choose.

Security and Reliability; Two Non-Negotiable Factors

Your payment gateway is exposed to cyberattacks, fraud attempts, and fake transactions. A reputable gateway should have at least the following security standards:

• Valid and mandatory SSL certificates for all payment pages
• Compliance with the PCI DSS standard for storing card information
• A system for detecting and preventing suspicious transactions (Fraud Detection)
• Two-factor authentication (3D Secure) for online transactions

Gateway reliability is equally important. During peak sales periods (such as seasonal sales), your gateway must be able to handle a high volume of concurrent transactions. Ask about the gateway's uptime and seek feedback from other stores on this matter. A payment gateway that goes down during peak sales days can cause irreparable damage to your business's reputation.

Summary; Final Checklist for Choosing a Payment Gateway

Choosing a payment gateway should not be viewed as a temporary or easily changeable decision. Switching between gateways is costly and may confuse your existing customers. Before signing the contract, review this checklist:

1. Calculate the total cost (percentage + flat fee + failed transactions) for your average cart value.
2. Ask about the settlement time in the worst-case scenario and factor it into your cash flow planning.
3. Test the payment experience from the customer's perspective (both on mobile and desktop).
4. Review the technical documentation and ready-made libraries, and simulate the integration in a test environment.
5. Ask the gateway's support team about response time and communication methods (phone, ticket, chat).
6. Carefully read the contract for hidden clauses (such as termination penalties or minimum monthly transactions).

By considering these criteria, you can choose a gateway that not only optimizes your costs but also provides a smooth and secure shopping experience for your customers. Remember that the best payment gateway is the one that aligns with your business model, transaction volume, and technical needs—not necessarily the most popular or the cheapest option on the market.