What is payment system API?
Payment system API, or Application Programming Interface, is a technology that enables different payment platforms to communicate and exchange information seamlessly. It allows businesses to integrate various payment methods into their systems, such as credit cards, bank transfers, and digital wallets. Payment system APIs make it easier for companies to process transactions, manage customer information, and track payment data. Overall, Payment system APIs are a crucial component of modern payment systems, ensuring secure and efficient transactions for businesses and their customers alike.

In today's dog-eat-dog business world, payment systems are a make-or-break factor for companies. They can be the ace up your sleeve, ensuring that your transactions are as safe as houses, or the fly in the ointment, causing you to lose clients and sales. That's where Application Programming Interface (API) comes into play, acting as a game-changer for payment systems by making it possible to integrate different payment platforms with ease.

In this article, we'll guide you through the ins and outs of selecting the right API for your business. According to MarketsandMarkets, the API management market is projected to be worth $5.1 billion by 2023, at a CAGR of 32.9%. By the end of this article, you'll be able to hit the nail on the head and choose an API that's the real McCoy, making your payment systems run like a well-oiled machine.

Understanding payment system API

If you plan to get to know payment system API, it can be like peeling an onion - it has layers upon layers of complexity. However, breaking it down into smaller parts can be a piece of cake.

How APIs work in the context of payment processing

APIs work by enabling communication between software applications and payment processors. It's like having a translator between two people who speak different languages - APIs translate the information from one system to another, ensuring that transactions are processed correctly.

For example, when a customer purchases on an e-commerce website, the website's application sends a request to the payment processor via the API. The API then retrieves the necessary information, such as the customer's payment details, and sends it back to the application. The application can then use this information to complete the transaction.

APIs make payment processing faster and more efficient. They eliminate the need for manual data entry and reduce the risk of errors. Additionally, APIs offer real-time updates on transaction status, making it easier for businesses to manage their finances.

Types of APIs

When it comes to payment system APIs, there are different types available, each with its unique features and benefits.

One such API is the RESTful API. RESTful APIs are like a breath of fresh air - they offer a simple, lightweight approach to integration. They use HTTP requests to retrieve and send data, which makes them flexible and easy to use. RESTful APIs are popular among developers because they're well-documented and widely supported.

Another type of API is SOAP, which stands for Simple Object Access Protocol. SOAP APIs are like a jack-of-all-trades - they support multiple programming languages and offer robust security features. They use XML to transfer data, which makes them reliable and efficient. However, SOAP APIs can be more complex to implement than RESTful APIs, which may make them less suitable for smaller businesses.

Aside from these two examples, there are also other types of payment system APIs available, such as GraphQL and JSON-RPC. The significance of these different APIs lies in their ability to meet specific needs and preferences. RESTful APIs may be suitable for businesses that prioritize simplicity and speed, while SOAP APIs may be a better fit for those that prioritize security and reliability.

Choosing payment API

Factors to consider when choosing a payment system API

When it comes to choosing a payment system API, there are several factors that businesses need to consider. It's like baking a cake - each ingredient plays a critical role in determining the final result.

Business model and target audience

One essential factor to consider is the business model and target audience. It's like choosing the right recipe - businesses need to select an API that aligns with their specific needs and goals. For example, a business that caters to an international audience may need an API that supports multiple currencies and languages. Similarly, a business that processes high volumes of transactions may require an API that can handle large-scale processing efficiently.

It's also important to consider the payment preferences of the target audience. Another crucial factor to keep in mind is the payment preferences of your customers. Some folks dig credit cards, while others prefer digital wallets or bank transfers. It's like speaking their lingo - choosing an API that supports the payment methods that your customers prefer can boost conversion rates and keep them happy.

Required features and functionalities

When choosing a payment system API, it's crucial to look for essential features and functionalities that align with your business needs. Here are some of the must-haves:

  1. Security: This is a top priority for any payment system. Look for APIs that offer secure payment processing, including fraud detection and prevention features.
  2. Integration: Ensure that the API integrates seamlessly with your existing systems and software.
  3. Payment methods: Look for APIs that support various payment methods like credit cards, debit cards, digital wallets, and bank transfers.
  4. Currency support: If your business caters to an international audience, ensure that the API supports multiple currencies.
  5. Customization: Choose an API that allows customization to meet your specific business needs.
  6. Reporting and analytics: Look for APIs that offer reporting and analytics features to help you track your payments and gain insights into your business's financial performance.
  7. Customer support: It's always good to have reliable customer support from the API provider to address any issues or concerns that may arise.

By considering these essential features and functionalities, businesses can choose an API that provides secure, reliable, and efficient payment processing services.

Integration with existing systems

Choosing an API that is compatible with existing systems can help businesses kill two birds with one stone - avoid the high costs and time-consuming development work involved in creating custom integrations. For instance, if a business uses a specific eCommerce platform like Shopify, WooCommerce, or Magento, selecting a payment system API that integrates with the platform can be a piece of cake, avoiding any technical difficulties and streamlining the integration process. Travel data is a top integration need as well. Each year, RapidAPI revises its compilation of the 50 most in-demand APIs. They ranked Skyscanner Flight Search API as the most sought-after API in 2021.

Moreover, API compatibility with existing systems can also help businesses avoid shooting themselves in the foot. It can ensure that the payment system's data is seamlessly synced with the business's existing systems, such as accounting or inventory management software, leaving no room for error. This can help businesses cut corners, streamline operations, and reduce the risk of costly mistakes that may result in lost revenue or customer dissatisfaction.

Scalability and future growth

When selecting a payment system API, businesses should make sure that they can walk the talk when it comes to scalability and future growth. This is especially important for businesses that anticipate growth or have seasonal fluctuations in transaction volumes. A payment system API that can handle increased transaction volumes during peak periods can help businesses keep their head above water, and prevent transaction failures, lost sales, and frustrated customers.

Moreover, the payment system API should be as flexible as a gymnast. It should be able to bend over backward and accommodate business model changes or expand into new markets. A payment system that can support new payment methods, currencies, or integrations with third-party services can help businesses stay ahead of the curve, keep up with the Joneses, and adapt to changing customer needs.

Security and compliance

When it comes to payment system APIs, businesses should take security and compliance factors seriously. According to a 2020 Statista report on API breakages and changes worldwide, approximately 60% of API users noted that their APIs rarely malfunction. It's better to be safe than sorry, right? This means choosing an API that doesn't cut corners when it comes to security and compliance.

One thing to consider is whether the API meets the requirements of industry standards such as the Payment Card Industry Data Security Standard (PCI DSS). This standard sets the bar high for protecting sensitive payment data and preventing fraud. If an API doesn't meet these standards, businesses may expose themselves and their customers to unnecessary risks.

Another factor to keep in mind is the API's compliance with data protection laws and regulations. With the ever-evolving landscape of data privacy laws, businesses should ensure that the API they choose doesn't cross the line, otherwise, they may find themselves in hot water.

Pricing and transaction fees

Payment System API

Pricing Structure

Transaction Fee


Flat rate based on monthly sales volume

2.9% + $0.30 per transaction


Flat rate based on monthly sales volume

2.9% + $0.30 per transaction


Flat rate or interchange plus pricing

2.9% + $0.30 per transaction (flat rate) or interchange fee + markup (interchange plus)


Interchange plus pricing

Interchange fee + markup


Monthly fee + a per-transaction fee

$0.10 per transaction + monthly fee

It's meaningful to note that the pricing structure and transaction fees of these payment system APIs may vary based on factors such as sales volume, funds amount, and currency used. Therefore, it's recommended that businesses carefully evaluate their needs and compare the pricing and transaction fees of different APIs before making a decision.

Popular payment system APIs

We'll take a look at some of the most popular payment system APIs on the market and compare their key features, benefits, and drawbacks.


Stripe is a recompense API that offers a developer-friendly platform with cutting-edge customization options. Its key features include support for over 135 currencies, subscription billing, and built-in fraud prevention tools. Stripe offers flexible pricing options, with transaction fees starting at 2.9% + 30 cents per transaction. However, its complex APIs and documentation may require some technical expertise to set up and use effectively.


PayPal remains one of the most popular recompense APIs, serving as an effortless and efficient solution for businesses of all scales to manage their financial transactions. It provides utter classical integration with major eCommerce platforms, catering to a diverse range of payment methods and currencies. Nonetheless, its transaction fees may seem steeper compared to other payment APIs, and its dispute resolution process may consume more time than anticipated.


Square is a popular revenue API that offers an all-in-one payment processing solution, including point-of-sale hardware and software, mobile payments, and online invoicing. It is known for its user-friendly interface and competitive pricing, with transaction fees starting at 2.6% + 10 cents per transaction. However, Square's integrations with third-party software can be limited, and its customer support has been criticized for being slow to respond to issues.


Klarna is a payment API that specializes in "buy now, pay later" financing options for eCommerce businesses. Its key features include installment payment plans, deferred payment options, and perpetual checkout experiences. Klarna charges a fixed percentage fee per transaction, but this can be higher than other payment APIs. Additionally, Klarna's services are only available in select regions, limiting its availability for global businesses.


Adyen is a payment API that focuses on providing a unified payment processing solution for global businesses. Its key features include support for over 150 currencies, in-house fraud prevention tools, and up-to-date reporting and analytics. Adyen offers flexible pricing options, with transaction fees starting at 2.8% + 30 cents per transaction. However, its complex reporting tools may require technical expertise to use effectively.


Authorize.Net is an all-inclusive payment API that furnishes a broad range of payment processing solutions such as mobile payments, eCommerce integrations, and prevention tools to combat fraudulent activities. The API's salient traits include its ability to cater to diverse funding methods and currencies, and its customizable checkout experiences. However, Authorize.Net levies a monthly fee, accompanied by transaction fees commencing at 2.9% + 30 cents for every transaction processed. It's essential to note that some users have encountered complications with its customer support and documentation.

Niche or specialized APIs

Braintree serves as a specialized payment API, offering funding processing solutions for mobile and web applications. Its standout features comprise customized checkout experiences, off-the-wall fraud prevention tools, and the ability to cater to multiple payment methods. Braintree does not charge any monthly fees, but a flat transaction fee of 2.9% + 30 cents applies for every transaction processed. However, businesses requiring extensive reporting and analytics may need to consider alternative options.

WeChat Pay stands out as a widely used repayment API in China, providing a seamless payment processing solution for businesses operating within the Chinese market. The API's key features include integration with the WeChat social media platform, support for multiple payment methods, and in-app payments. WeChat Pay levies a transaction fee of 0.6% + 0.1 yuan for every transaction, making it a cost-effective choice for Chinese businesses. However, WeChat Pay's limited availability outside of China may not suit the needs of global businesses.

Each payment API has its own unique features, benefits, and drawbacks, making it important for businesses to carefully consider their needs and priorities when selecting a payment processing solution.

API implementation and testing best practices from Corytech’s experts

API implementation and testing are crucial to the success of any business that uses APIs. It's essential to follow best practices for integrating APIs to ensure invariable integration and avoid potential problems.

Integrating APIs is no piece of cake and requires careful planning, documentation, and communication with all stakeholders involved. It's crucial to have a clear picture of the objectives and goals of the API integration to ensure that it fits the overall business strategy like a glove. This involves identifying the specific requirements of the integration, such as the type of data that needs to be transferred, the frequency of updates, and the security protocols that need to be followed. The planning stage also involves identifying potential roadblocks and developing backup plans to ensure smooth sailing for business operations.

Documentation is another vital aspect of API integration. Clear and concise documentation ensures that all stakeholders have a crystal-clear understanding of the integration process, including the expected outcomes and timelines. It's essential to document every step of the integration process, from the initial planning phase to the final implementation and testing. This helps to ensure that all parties are singing from the same hymn sheet and can swiftly troubleshoot any issues that may arise during the integration process. Effective communication is also key throughout the integration process to ensure that everyone is in the loop about any changes or updates to the integration plan.

When integrating APIs, testing is a make-or-break step that ensures everything is functioning as planned. Testing the functionality of the API is like putting it through its paces to confirm it's working as intended and delivering accurate results. Besides, it's vital to conduct security tests to pinpoint any weaknesses that could lead to unauthorized access or data breaches. Additionally, performance testing is crucial to determine whether the API can handle the expected volume of transactions without encountering lags or system failures.

Payment system integration FAQ

What is payment system integration?

Payment system integration involves the linkage of an online store or application to a payment gateway or processor, enabling the acceptance of electronic payments. This process requires the seamless exchange of information between the two systems, ensuring secure and efficient processing of transactions. Integrating payment systems helps businesses simplify their payment processing by providing a variety of payment options, thus enhancing the customer checkout experience. By streamlining their payment processing, businesses can concentrate on other vital aspects of their operations, such as customer engagement and satisfaction.

Which payment gateway API is best?

There are many different payment gateway APIs available, but it's hard to say which one is the best because it depends on the needs of the business. Some popular options include PayPal, Stripe, and Square.

What is the difference between a payment gateway and a payment API?

A payment gateway serves as a vital service that processes online payments, enabling businesses to accept electronic payments using various online payment methods like credit or debit cards, bank transfers, and more. By linking the business's website or application to the payment processing network, the payment gateway securely transmits payment data between the two entities, ensuring secure and reliable payment processing.

Conversely, a payment API is a software interface that allows businesses to integrate payment processing functionality into their software applications. It provides developers with the flexibility to customize the payment processing experience, including designing custom user interfaces and creating personalized payment pages. This helps businesses tailor their payment processing to suit their unique needs, enhancing the customer experience and streamlining their operations.

What’s Next?

In conclusion, optimizing payments can be made much easier with the right payment system API. Corytech offers an innovative and fully-featured platform that can help any business. Requesting a personalized demo can help you see how Corytech can work for your business.

Corytech Team
Written by Corytech Team