Best Payment Processing APIs & SDKs for Developers

June 5, 2023

a photo depicting a payment processing API

Simplify Payment Processing Integrations

It can be a major hassle to find a developer friendly credit card processor or switch all of your company's internal products over to a new payment processor. Third-party payment gateways, outdated systems, and poort customer support teams can all create operational hurdles and extra work for your IT department. For this reason, small businesses and software firms are increasingly turning to payment processing APIs for a simple way to integrate credit card processing with their apps, websites, and software applications. If you have existing internal software that you want to accept debit and credit card payments, or if you sell a software product that needs to process digital transactions, your most seamless and future-proof option will be a reliable credit card processing API provided by a tech-forward payment processing company.

How to Choose a Top Payment Processing API or SDK

Choosing a credit card processing API or SDK requires several things to be considered in addition to the company's technology and documentation. Below are several items you will want to ensure align with your objectives:

Features and Capabilities: The API should support all popular payment methods, such as credit cards, debit cards, digital wallets, bank transfers, and ACH. Other desired features could include fraud prevention and multi-currency support.
Reliability: Check the uptime and performance history of the API. APIs provided by established companies often have robust infrastructure and high reliability.
Cost: Understand the pricing model. Some companies only charge per transaction, while others have additional fees for accessing the API. We recommend companies that offer “Interchange-plus” or flat-rate pricing with no monthly or annual fees. We'll cover pricing in the picks below.
Security: Ensure the API follows best practices for payment security, such as PCI-DSS compliance. The company should use secure data transmission methods, such as HTTPS and data encryption.
Customer Support: Consider the support offered by the API provider. Quick, reliable phone support can be very helpful when dealing with payment-related issues. Some of the most popular providers have poorly rated support.
Scalability: As your business grows, the API should be able to handle increasing numbers of transactions.
Regulatory Compliance: The API provider should comply with all relevant regulations in the regions where you do business. This can include GDPR for Europe, CCPA for California, and so on.
Client Reviews: Look for reviews and feedback from other developers who have used the API. This can provide valuable insights into potential issues and the quality of the service. Below, we chose providers that have the best reputations.

Our Top Picks for Credit Card Processing APIs and SDKs

To help you find a payment API that will save you time and money, we've compiled the following list of the top payment processing APIs and SDKs. The processors on this list offer easy-to-integrate APIs and low-commitment contract terms and competitive pricing.

#1 Helcim

Helcim is our top pick for developer-friendly credit card processing integration for a variety of reasons.

Modern Technology

First, Helcim has a well-established developer toolkit and API for quick payment integration integration into nearly any app or website. The API is well-documented and offer over 80 possible actions to list, create, view, or modify a large number of data objects. Second, Helcim.js makes it easy to customize the front-end experience you want your customers to have. Everything about the sale can happen in the app or an the website without any security drawbacks.

Hardened Security

Speaking of security, Helcim is one of the most progressive processors in the industry when it comes to protecting you and your customers from data breaches. The company's technology allows developers to create seamless transactions on the front end without sending any sensitive credit data to your own servers. This is not only the recommended and most PCI compliant way to accepting transactions, but removes your liability for card fraud data breaches. Such breaches can be extremely costly to a business, both in the form of fines and losses of merchandise.

Best In-Class Pricing

Helcim has the best pricing in our expert opinion. The company has no monthly fees, no annual fees, and no junk fees at all, which is very rare among credit card processors. Add to this that Helcim offers “Interchange-plus” pricing at a modest markup starting at 0.50% and $0.25 per transaction for online transactions, and you have a provider that is unmatched in technology and cost. Helcim's processing fee markup has automatic volume discounts. The more you process the lower the markup gets. As far as this reviewer is aware, Helcim is the only processor that offers such a pricing model.

Top-Rated Customer Support

Unlike some of the top payment APIs in the industry, Helcim offers dedicated phone support. This means that you can actually talk to a person if you are hitting a roadblock in your development process. Most other APIs of similar technological quality only offer chat and email support. If they do offer phone support, it often comes at an additional cost or requires that you process a high level of sales. At the end of our research, Helcim stood far and above in customer support reviews.

Contact Helcim

For all of the details regarding Helcim's API and credit card processing services, visit the company's website here or call (888) 506-7812.

#2 CDG Commerce

E-Commerce Specialists

Located in Chesapeake, Virginia, CDG Commerce is a great option for standard-risk merchants of all sizes and types. CDG has been privately owned since 1998 and offers a proprietary payment gateway (as well as a discount on Authorize.Net’s payment gateway), a virtual terminal, QuickBooks integration, mobile phone processing, sales reporting, security breach protection, and vulnerability scanning. CDG Commerce's Quantum Gateway offers multiple database engine APIs to choose from.

CDG Commerce Pricing

CDG Commerce has three pricing options to choose from with each offering competitive rates and fees with options for no annual fees, monthly minimums, or termination fees. CDG also offers next day funding to most business types. CDG has earned an “A” rating in our review as well as an “A+” rating with the BBB.

For more information, see the CDG Commerce website or call (888) 393-1079.

#3 Stripe

Lastly, we couldn't finish out this list without including one of the most popular payment APIs in the industry. When is comes to features and integrations, Stripe is unmatched in its offerings. The company offers competitive flat-rate transaction processing fees with no monthly or annual fees, and no service length commitments. There are several optional services that can be added for varying monthly fees. Stripe is a great option for larger scale operations as it has numerous enterprise clients, like Uber and Shopify. However, smaller businesses have reported numerous grievances with the company's customer support, or lack thereof. Getting setup with Stripe is also very quick and in many cases you can begin running sales the same day that you signed up. This makes it a good option for brand new ventures that want a low commitment option. Overall, we like Stripe for businesses that need rapid scalability at enterprise levels or for test out business ideas.

For all the detail, see our Stripe review.

Final Thoughts

When selecting a payment processing API, software and app developers should prioritize an API's feature set, ease of integration, reliability, cost, security, support, scalability, regulatory compliance, as well as the reputation and stability of the API provider. Each of these factors will significantly impact the performance, user experience, and overall success of the application. The best choice will depend on the specific needs and circumstances of each business. Developers must therefore thoroughly assess their options to make an informed decision. We have done out best to provide the best payment processing APIs above.

About The Author

Phillip Parker

In the late 2000s, as a broke college student struggling to make ends meet, I was contacted by a merchant services company after uploading my resume to a job listings website. This company promised substantial commissions and ongoing residual income for simply persuading businesses to accept credit card payments. It seemed straightforward enough—after all, what business doesn’t need to process credit card payments? Following a phone interview with a persuasive “sales director,” I found myself embarking on what I believed would be an easy job that would significantly boost my bank account with reliable monthly income and large sales commissions. However, the lessons I learned would profoundly change my life in ways I could never have imagined.

After completing my sales training, I hit the ground running, eager to make sales. This broke college student was determined to improve his financial situation! My first attempt at a cold call, with no prior appointment, ended with a burly man in his 50s yelling at me to leave, claiming he had been “totally robbed” by someone like me before. As I hastily exited, puzzled and intimidated by his reaction, I couldn’t help but wonder what he meant. Throughout the day, I encountered similar hostility from other business owners, all expressing disdain for the industry I had been so excited to join that morning. Confused and curious, I decided to shift my approach from selling to listening.

I quickly uncovered that the merchant services sector was riddled with unethical practices, including hidden fees, deceptive marketing, fine-print traps, and much more. It dawned on me that I had nearly been tricked by a dubious company into selling overpriced services under contracts with long-term commitments, all without being fully aware of what I was promoting. Outraged, I resigned from that company but learned that there were indeed ethical credit card processing companies that treated their clients fairly. Over the next four years, I worked for one such company, assisting hundreds of businesses in securing cost-effective processing solutions. Yet, I also met many more who had been misled and trapped in onerous service agreements. Determined to help people steer clear of these unscrupulous providers, I launched this website in my spare time, dedicating myself to researching and sharing my findings on every merchant account provider I could investigate.

Gradually, more and more business owners began to discover my articles. As word spread, search engines started to rank my content highly, amplifying its reach. My efforts were making a difference! Eventually, the website garnered enough traffic to enable me to leave my job and focus on it full-time, a journey that has now spanned over a decade. This path has not been without its challenges; unscrupulous company owners have tried to intimidate and sue me into silence on several occasions. Yet, I have stood firm against each threat. Here I am, continuing to publish reviews and articles, hoping to safeguard others from the pitfalls of the credit card processing industry.

If you believe in my mission and wish to contribute, please share my articles on your websites and social media. Thank you for visiting!

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