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November 22, 2022

How to Add Payment Processing to a Website

Merrell Sheehan

Written by:

Merrell Sheehan

How to Add Payment Processing to a Website

Whether you’re selling handmade scarves, 3D-printed toothbrushes, or custom artwork, you need an eCommerce site with the power to process customer payments. 

So, how do you add payment processing to a website? While the general process is pretty simple, the nitty-gritty work takes some in-depth technical expertise—and if you’re not a cybersecurity expert, an accountant, or a master web developer, the idea can seem daunting.

Electronic Merchant Systems has over 30 decades of payment processing experience under our belts. So, we’re here to teach you how to add payment processing to a website by defining some key terms, breaking down the entire process into six steps, and answering a few FAQs. 

Table of Contents:

What Should You Know Before You Start the Payment Processing Procedure?

Before we get started, let’s define some key terms:

  • Web host – Simply put, a web host is a service that keeps your website—and its functions—available and accessible on the internet. They offer a chunk of cyber-real estate, and you rent it from them, usually for a monthly fee.
  • Merchant services – Merchant services (sometimes called merchant accounts) debit money from your customers’ checking or credit accounts and transfer those funds to your business account. They’re the middleman between your clients’ banks and your bank.
  • Payment gateway – A payment gateway is the digital interface that accepts your customers’ credit/debit card numbers and communicates the transaction details with your merchant services provider.
  • External gateway vs. direct (“transparent”) gateway – An external gateway redirects your customers to a third-party web page to complete their transactions. Alternatively, a direct (sometimes called “transparent”) gateway performs the payment process on your site without redirecting to another page. 

Incorporate Payment Processing Into Your Brand website in 6 Steps

With definitions out of the way, let’s break down how to add payment processing to your eCommerce site. 

#1 Ask Your Website Host About Payment Gateway Compatibility

Your website host may:

  • Only allow you to use certain payment gateway brands (for cybersecurity or compatibility reasons)
  • Offer in-house gateway services to cut out the middleman
  • Recommend one or multiple brands, but may not require you to choose one of their partners

It’s crucial that you ask the host about any of the above before signing on the dotted line—ideally before you even choose your web host. 

#2 Choose a Payment Gateway

Once you know what your web host will allow, it’s time to choose a payment gateway for your eCommerce site. But, while you’re browsing, there’s another player to keep in mind—your website’s shopping cart software. 

While they’re building your site, your web developer will likely use third-party software to build a shopping cart system that:

  • Keeps track of what your customer wants to buy
  • Applies discounts
  • Displays the visuals of the checkout process to your client 

Keep in mind that your gateway of choice will also have to play nice with your shopping cart software—your web developer can help you choose a compatible gateway.

#3 Sign Up for Merchant Services (AKA a Merchant Account) and Link Them to the Gateway

If you plan to accept credit and debit cards for purchases, you simply can’t do business without a merchant services provider. While shopping for a provider, ask them about:


  • Their fee structureMerchant services providers typically charge three kinds of fees:
    • Interchange fees (which go to the credit card company)
    • Payment processor fees (which go to the merchant services provider)
    • Assessment fees (which also go to the credit card company, but they’re based on monthly sales instead of per-transaction percentages)
  • Their additional services – Ask about loyalty program administration, point of sale (POS) system rentals, and statement services. 
  • How to save on merchant services – A good provider will offer free rate reviews to their members, negotiate their rates with credit card companies, and help businesses build processing fees into the prices of items. 

Once you choose a provider, send them the information they’ll need to connect to your payment gateway. 

#4 Build Your eCommerce Store

Building an eCommerce store is the subject of many (much longer) articles, and it isn’t always a simple process. We recommend hiring a web developer for this process because:

  • It can be cheaper than doing it yourself (if you’re not a tech whiz or master coder).
  • A professional can help you build a secure site that your clients can trust.
  • They understand how all the moving parts fit together—web hosting, shopping cart software, payment gateways, and website functionality.

#5 Add Your Accepted Payment Methods to the Store

Like the step above, we recommend entrusting your web developer with the task of adding payment methods to your site for a few reasons:

  • Typically, a single payment gateway will handle all card types you desire to accept, which means one gateway will work for Visa, Mastercard, Discover and American Express.
  • A coding expert can help your website look and play nice with your chosen gateway.
  • You want your site and your payment infrastructure to be airtight from a cybersecurity standpoint.

#6 “Testing, 1, 2… Is This Thing On?”

Your payment gateway should offer a method for testing the entire process top-to-bottom to make sure it works. During the testing process, make sure that all of the following work as expected:

  • All of the payment methods you accept (e.g., Visa, MasterCard, and American Express)
  • Discount codes or sales (make sure the price changes to reflect the “deal”)
  • Communication between the gateway and your merchant services provider
  • Acceptable page load times between your site and the external gateway, if you’re using one

And going forward, you should test the process if you make any changes to your gateway, web host, shopping cart software, or merchant services provider. 

Frequently Asked Questions About Website Payment Processing

The process described above is (purposefully) general—each of the steps could take up an entire article. But let’s address some questions you likely have after reading through the procedure.

Do I Have to Hire a Web Developer, eCommerce Site Builder, Payment Gateway Provider, and Merchant Services Provider?

For the same reason that each of the above steps is described in limited detail, you probably want to hire experts for anything you don’t know how to do yourself when it comes to eCommerce—when you zoom in, it’s a complicated procedure. 

Even if you think you can handle it after a few YouTube tutorials, you should probably still consider hiring these tasks out because:

  1. Both learning and building take time—as a business owner, you have enough on your plate.
  2. Cybersecurity is critical to eCommerce—secure sites protect both you and your clients from fraud.

How Much Is All of This Going to Cost?

The cost of your eCommerce site-building will depend on:

  • The cost of your web hosting services
  • The size and complexity of your site and inventory
  • Your merchant services provider’s fees
  • The amount of time and expertise your web developer will need

But remember that this will mostly constitute a one-time cost. Once your site is done, you’ll only need to perform software updates and regular maintenance. 

Where Can I Find More Expert Help?

Luckily, everyone you hire to help you build an eCommerce site can offer:

  • Their industry-specific expertise
  • Recommendations for other experts
  • Software and web hosting preferences

The top qualification you should look for in an expert is their experience—how many sites have they built? The more experience they have, the more knowledgeable your service provider will be about eCommerce sites that work. 

What's Next?

Generally speaking, adding payment processing to your website is simple—but each phase in the process requires in-depth expertise, which is why we recommend consulting with experts as often as possible. 

When it comes to expertise and experience in the merchant services sphere, no one bests Electronic Merchant Systems. We’re far from newcomers to eCommerce and credit card processing—we’ve been working with brands just like yours for over three decades. 

We offer traditional merchant services but can also provide POS equipment, help you build loyalty programs, consult on surcharges and cash discounts, and so much more. 

Our solutions are developed with your business—and your bottom line—in mind. Request a consultation to learn more about how we can help your business grow. 

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