eCommerce Payment Processing: What It Is and How It Works

Navigating online payments doesn’t require a degree in finance. Whether you are launching a new retail store, have recently started an online business or are just curious about how your business’s payments move on the internet, this guide covers the basics of eCommerce payment processing, from checkout to settlement.

What you’ll learn:

• The basics of how eCommerce payment processing works
• Different types of eCommerce payment methods
• Key advantages of eCommerce payment processing vs. traditional methods
• How to choose an eCommerce payment provider

What is eCommerce payment processing?

eCommerce payment processing is the mechanism that captures and transfers funds from a customer to a merchant following an online transaction or counter payment with a card or digital wallet.

At its core, the payment processor acts as the intermediary that securely transmits your customer’s payment data between the parties involved – specifically from your merchant website or point of sale (POS) through the acquiring bank and to the card networks. The processor’s primary role is to facilitate the communication and authorisation of the transaction in real time, ensuring the funds are valid and available before confirming the order, and then handling the subsequent transfer of money into your merchant’s account.

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eCommerce payment processing features

eCommerce payment processing relies on a seamless integration of several key components to authorise and settle transactions. The main elements include:

• Payment gateway: The digital equivalent of a physical POS terminal, a payment gateway securely captures your customer’s payment information at checkout and encrypts it for transmission.
• Payment processor: The intermediary that communicates between your bank (acquiring bank) and the financial networks to verify the transaction details, check for available funds and obtain authorisation.
• Merchant account: A specialised bank account that holds the funds from customer transactions temporarily before they’re transferred to your business’s primary business bank account.
• Acquiring bank: The financial institution that maintains your merchant account, receives funds from the card networks on behalf of the seller and manages your risk as a merchant.
• Card networks: A payment technology company, like Visa or Mastercard, that acts as the bridge between the acquiring and issuing banks to route transaction details and facilitate the clearing and settlement of funds.

How does eCommerce payment processing work?

Understanding the flow of an online transaction helps demystify where money goes between the click of a button or tap of a card and the deposit in your business bank account. While the process involves multiple parties, it typically happens in seconds. Here’s how eCommerce payment processing works.

1. Customer submits payment

The journey begins at checkout, where your customer enters their card details through your online store or uses a digital wallet at your POS. At this moment, your customer’s browser or the payment form captures the data and prepares it for secure transmission, initiating the entire chain of events.

2. Payment gateway encrypts and transmits

Once your customer hits a ‘Pay Now’ button or taps their card at your physical POS, the payment gateway takes over. Its job is to encrypt the sensitive data and forward it to the payment processor. The gateway acts as the secure bridge between your POS and the financial networks.

3. Processor routes to card network

The payment processor receives the encrypted transaction details and routes the information to the appropriate card network (such as Visa, Mastercard or American Express), which then identifies the bank that issued the customer’s card. The processor ensures the message reaches the correct destination.

4. Issuing bank authorises/declines

Next, your customer’s issuing bank receives the request and performs a series of checks: confirming the card is valid, that funds are available and that there are no indications of fraud. The bank then sends an authorisation code (or a decline notice) back through the card network, processor and gateway to you, the merchant, usually in just 2–3 seconds.

5. Funds settlement

While your customer sees an immediate ‘Approved’ message, the actual movement of money occurs later. At the end of the business day, your payment processor will submit a batch of all authorised transactions for settlement. The card network then coordinates the transfer of funds from the issuing bank to your acquiring bank.

6. Merchant receives payout

Finally, the acquiring bank deposits the funds, minus any processing fees, into your business bank account. Standard payouts typically take 1–2 days, though some modern processors offer next-day or even same-day settlement. The entire authorisation process takes seconds, but the final deposit can take a few days to clear.

eCommerce payment methods

To cater to diverse customer preferences and maximise conversion rates, modern businesses must offer a variety of payment options.

Credit cards

Credit cards remain the dominant eCommerce payment method. For merchants, credit card payments are typically processed through the major card networks (Visa, Mastercard, American Express) and offer strong fraud protection, though they come with higher processing fees than some other payment methods.

Debit cards

Debit cards function similarly to credit cards in the checkout flow, but the funds come directly from your customer’s debit account. Because the money is pulled immediately rather than borrowed (as with a credit card), debit card transactions generally have lower processing fees for merchants.

Bank transfers

Bank transfers, often facilitated through services like PayID, allow your customers to pay directly from their bank account without using a card network. This method is usually cheaper than card payments since it avoids card network fees.

Buy now, pay later

Buy now, pay later (BNPL) services allow customers to split a purchase into smaller, interest-free instalments paid over time. Providers like Afterpay assume the credit risk and pay merchants upfront (minus a fee), making it an attractive option for increasing average order values.

eCommerce payment methods comparison

Choosing the right payment methods for your online store requires balancing transaction speed, cost and customer preferences. Here’s a quick comparison of the most common options.

The differences between eCommerce payment processing and traditional payment processing

The fundamental difference between traditional and modern eCommerce payment processing lies in the customer’s checkout experience. Traditional gateways often redirect the buyer to a third-party payment page, temporarily taking them away from the merchant’s website to complete the transaction. In contrast, modern eCommerce payment processing uses an integrated gateway, where the payment form is seamlessly embedded within the merchant’s own checkout flow, keeping the customer on the site from start to finish.

Here’s a side-by-side comparison of integrated eCommerce payment processing and third-party systems:

For businesses seeking a simple yet powerful all-in-one solution, a Square website offers fully integrated payments that keep customers on your site. It combines a customisable website builder with secure, built-in payment processing, automatically syncing your online and in-person sales, inventory and customer data.

Pro Tip: With traditional processors, you often need to apply for a separate merchant account, which can be a lengthy and complex hurdle. When you sign up with Square, you get a merchant account built directly into the system, allowing you to start accepting payments immediately without any additional applications or fees.

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Considerations when choosing an eCommerce payment provider

Selecting the right eCommerce payment provider is one of the most consequential decisions you’ll make for your online business. Here are some considerations for choosing the payment provider that best fits your business needs.

Security and PCI compliance

Protecting customer data is a legal requirement. The Payment Card Industry Data Security Standard (PCI DSS) mandates that all businesses handling cardholder data must maintain a secure environment, with compliance levels determined by your transaction volume. Consider choosing a payment processor, like Square, that simplifies PCI compliance by building it into its platform.

SSL encryption support

Secure Sockets Layer (SSL) encryption creates a protected channel between your customer’s browser and your website, ensuring that data transmitted during checkout cannot be intercepted by malicious parties. Ensure your eCommerce payment provider offers the following:

• Data protection, including payment details and personal information, that undergoes SSL encryption during a transaction
• Visual indication of SSL protection through padlock icons and ‘https://’ in the address bar, signalling security to shoppers

Accepted payment methods

Offering the right mix of payment options directly impacts your conversion rates and ability to serve diverse customer preferences. Look for an eCommerce payment provider that offers:

• Acceptance of all major card brands including Visa, Mastercard and American Express
• Support for digital wallets including Apple Pay, Google Pay and PayPal
• Alternative payment methods like BNPL and bank transfers
• Uniform fees across card brands

International and multi-currency support

If you plan to sell across borders, your eCommerce payment provider must be able to handle the complexities of global commerce, including:

• Currency conversion that provides for the display of prices and processes transactions in local currencies
• Cross-border fees transparency so customers understand additional charges for international transactions
• Regional payment methods that support local options where you sell
• Ability to navigate regulatory compliance variations across borders

Tokenisation capabilities

Look for a payment provider that offers tokenisation capabilities that replace sensitive card data with unique digital identifiers and convenient features. Tokenisation provides:

• Security benefits for you and your customer: Even if your systems are breached, stolen tokens are worthless to fraudsters because they cannot be reverse-engineered.
• Easy and secure billing and payment options: Tokenisation enables secure recurring billing and one-click checkouts, and reduces your PCI compliance scope since sensitive data isn’t stored on your servers.
• Customer confidence: Communicating that you use tokenisation reassures customers about the safety of their financial information.

Transaction fees

Fee structures vary significantly between providers and directly impact your profit margins. Carefully evaluate the following when considering an eCommerce payment provider:

• Pricing models: Providers may charge flat-rate pricing (simple percentage + fixed fee), interchange fees (pass-through costs + markup) or tiered rates based on transaction type.
• Rate variations: Expect different fees for in-person transactions, online payments and manually entered cards (higher due to fraud risk).
• Additional costs: Watch for monthly statements, chargeback fees, PCI compliance fees and early termination penalties.
• Volume considerations: High-volume businesses may qualify for custom pricing; some providers offer reduced rates as your processing grows.

With Square, you pay a flat rate for every online sale. There are no contracts, no monthly minimums and no separate gateway fees. Payments, fraud protection, PCI compliance and reporting are built in.

Ease of integration

How easily a payment solution integrates with your existing systems affects your launch timeline and ongoing operational efficiency, so be sure to consider the following before choosing an eCommerce payment provider:

• Technical requirements: Some providers require significant development work, while others offer plug-and-play solutions.
• Setup complexity: Consider whether you need coding expertise or if you can use pre-built integrations, website builders or simple payment links.
• Ongoing management: Evaluate the administrative dashboard for ease of viewing transactions, managing refunds and accessing reports.
• Hardware needs: If you also sell in person, consider whether the provider seamlessly connects online and physical sales channels.

Scalability for future growth

Your eCommerce payment provider should grow with your business, accommodating increased volume and new sales channels without requiring painful migrations:

• Ensure the provider can process peak-season traffic spikes and higher transaction volumes as you expand.
• Look for solutions that support adding new sales channels, like pop-up shops, marketplaces or international stores, without switching providers.
• Check for advanced reporting, subscription management or custom checkout experience capabilities.
• Seek contract flexibility or processors with no contracts so you’re not locked into long-term commitments that may not meet your future needs.

Best practices for accepting eCommerce payments

• Optimise your checkout process to reduce friction for legitimate customers. Offer a seamless experience across devices, minimise the number of form fields, and implement features like one-click payments for returning buyers.
• Establish clear policies that explicitly outline your refund, return and dispute procedures to help deter fraudulent claims and provide a legal foundation for challenging false chargebacks, also known as ‘friendly fraud.’ This is when a customer makes an online purchase, for example, but then notes it as fraudulent or unauthorised and requests a chargeback.
• Offer a variety of payment methods to not only cater to customer preferences but to spread risk across payment types like credit/debit cards, digital wallets and BNPL.
• Use a reputable eCommerce payment provider that offers robust, built-in fraud detection tools.
• Monitor fraud by continuously analysing transaction data for suspicious patterns and trends. Implement real-time monitoring tools that use behavioural analytics and velocity checks (flagging unusually high activity from the same card, account or IP address) to identify and block fraudulent activities without disrupting the shopping experience for genuine customers.

How to choose an eCommerce payment provider that scales with your business

When evaluating eCommerce payment providers, it’s critical to choose one that can scale with your business. Look for a provider that can support increasing complexity and volume without requiring a costly or disruptive switch.

Square, for example, offers custom pricing packages for businesses processing over $250,000 per year, plus partnerships with service providers like Wix, QuickBooks and DoorDash, meaning you can easily integrate new tools for accounting, inventory management and multichannel selling.

Discover how the Square all-in-one platform can provide the flexible foundation you need to build an eCommerce store that scales alongside you.

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eCommerce payment processing FAQs

What is an example of an eCommerce transaction?

An example of an eCommerce transaction is a customer purchasing a pair of shoes from an online retailer and paying for them via credit card through a digital checkout page.

What is the common payment method used in eCommerce?

Credit and debit cards remain the most common payment methods used in eCommerce transactions globally.

How long does eCommerce payment processing take?

eCommerce payment processing typically takes anywhere from a few seconds to a few business days for transaction approval and funds settlement in the merchant’s account.

What fees are associated with eCommerce payment processing?

Fees associated with eCommerce payment processing usually include a percentage of the transaction amount, a small fixed per-transaction fee and sometimes monthly statement or gateway fees.

Is eCommerce payment processing secure?

Yes, eCommerce payment processing is secure, as it relies on technologies like encryption, tokenisation and compliance standards such as PCI DSS to protect sensitive data.