AgilityPortal Insight Blog

Informational content for small businesses.
Back to Blog
  • Digital Transformation
  • Blog
  • 10 Mins

Everything You Need to Know About Developing a Payment Gateway

Everything You Need to Know About Developing a Payment Gateway
Everything You Need to Know About Developing a Payment Gateway
There are benefits to building your gateway from scratch, including full creative control. Click here to learn how to create a payment gateway.

Posted in: Digital Transformation
Everything You Need to Know About Developing a Payment Gateway
Everything You Need to Know About Developing a Payment Gateway
A payment gateway serves as a crucial component for e-businesses and online retailers, facilitating the secure processing of credit card or direct payments. Acting as the intermediary link between a merchant's website and their acquiring bank, it ensures the seamless transfer of sensitive financial data during transactions.

In essence, a payment gateway acts as a virtual bridge, allowing customers to securely submit their payment information on the merchant's website. This information is then encrypted and transmitted to the acquiring bank for authorization and processing. 

By providing this essential service, payment gateways play a pivotal role in enabling online businesses to accept payments from customers in a safe and efficient manner.

In this article, we will dig deeper into the intricacies of payment gateways, exploring their functionalities, significance for e-commerce businesses, and key considerations for selecting and implementing the right solution. 

What is a payment gateway?

Before embarking on the endeavor of creating your own payment gateway, it's essential to clearly define its purpose and functionality. 

A payment gateway serves as the intermediary system that enables your website to accept payments via credit and debit cards. It acts as the conduit between the customer, your business, and the payment processor. 

This involves providing a secure payment portal or checkout page where customers can input their payment information, encrypting this sensitive data, and transmitting it securely to the payment processor or bank. When developing your own payment gateway, it's crucial to prioritize these core functions and ensure compliance with PCI requirements and relevant anti-fraud regulations.

So, which businesses might be most inclined to explore the creation of custom payment gateways? 

Typically, larger enterprises that seek independence from third-party providers or those experiencing rapid expansion and require a tailored solution to meet their specific requirements would be the primary candidates. 

These businesses may find that developing their own payment gateway offers greater control, customization, and scalability to accommodate their evolving needs and business strategies.

Why do you need a payment gateway?

Why do you need a payment gateway

A payment gateway is essential for any online business that intends to accept payments electronically. Here are four reasons why you need a payment gateway:

  • Secure Payment Processing - A payment gateway ensures the secure transmission of sensitive financial data between the customer, merchant, and the acquiring bank. By encrypting payment information, such as credit card details, the gateway protects against unauthorized access and fraudulent activities, providing peace of mind to both businesses and customers.
  • Expanded Payment Options - Payment gateways support various payment methods, including credit and debit cards, digital wallets, and bank transfers. By offering a range of payment options, businesses can cater to the diverse preferences of their customers, thereby enhancing convenience and satisfaction. This versatility also helps businesses reach a broader audience and increase sales opportunities.
  • Streamlined Checkout Experience - Integrating a payment gateway into your website streamlines the checkout process for customers. With a user-friendly interface and seamless navigation, the gateway simplifies payment submission, reducing the likelihood of abandoned carts and improving conversion rates. This enhanced shopping experience contributes to customer loyalty and retention.
  • Compliance and Regulation - Payment gateways ensure compliance with industry regulations and standards, such as the Payment Card Industry Data Security Standard (PCI DSS). By adhering to these guidelines, businesses demonstrate their commitment to data security and regulatory compliance, mitigating the risk of fines, penalties, and reputational damage. Additionally, payment gateways provide features and tools to facilitate compliance monitoring and reporting, further enhancing data protection measures.

In a nutshell, a payment gateway is indispensable for online businesses seeking to facilitate secure, convenient, and compliant payment processing. By leveraging the capabilities of a payment gateway, businesses can enhance customer trust, expand their market reach, and drive growth in the digital marketplace. 

How Payment Gateways Work

Payment gateway development services serve as a bridge connecting a merchant's online platform with a payment processor, enabling the seamless transmission of payment data between the merchant's website or application and the processor. 

Let's explore the roles and functions of the key parties involved in payment processing:

  • Payment Service Provider (PSP) or Payment Processor - This is a third-party company that offers payment processing services to merchants. These services include providing the payment gateway, managing card issuing, implementing risk and fraud management solutions, facilitating acquiring, and supporting various global payment methods.
  • Merchant - A merchant refers to any entity that sells goods or services, whether through online platforms or physical stores.
  • Customer or Cardholder - This is the individual who initiates a purchase of goods or services from a merchant.
  • Issuer, Issuing Bank, or Card Issuer - An issuer is a bank or financial institution responsible for issuing payment cards to customers on behalf of card schemes. They verify the cardholder's account status, ensuring there are sufficient funds and conducting security checks during transactions.
  • Acquirer, Acquiring Bank, or Acquiring Member - The acquirer is a financial institution that processes card payments on behalf of merchants. They securely transmit payment data to the card schemes for authorization by the issuer.
  • Payment Gateway - A payment gateway is the technology used by merchants to authenticate and securely transmit payment data between the acquirer, issuer, and card schemes. Once the payment is authorized by the acquirer, the payment gateway sends a verification message back to the merchant.
  • Card Schemes - These are entities that link acquirers to issuers, enabling the exchange of card transaction information during the authorization process. Well-known card schemes include Mastercard, Visa, American Express, Discover, and UnionPay.

These parties collaborate to ensure the smooth and secure processing of payments, enabling seamless transactions between merchants and customers.

Main Components of a Payment Gateway

A payment gateway has several core components that work together to facilitate online payments:

  • Merchant Account - This is a type of bank account that allows businesses to accept credit card payments. The merchant account is set up through an acquiring bank that partners with payment card networks like Visa and Mastercard. The merchant account stores funds from processed transactions before they are deposited into the business's checking account.
  • Payment Processor - The payment processor handles the transmission of payment data between the customer, merchant, issuing bank, and card network. It verifies credit card information, checks for sufficient funds, obtains authorization, and settles the transaction. Top processors include Stripe, Braintree, and PayPal.
  • PCI Compliance - PCI stands for Payment Card Industry, and the PCI Data Security Standard is a set of requirements designed to ensure the safe handling of credit card data. Gateways must adhere to PCI compliance standards to operate securely. This involves file encryption, access controls, network security, and more.
  • Gateway Software/API - The gateway software acts as the interface between the merchant's website and their payment processor, allowing online transactions to be completed seamlessly. Gateways provide APIs that developers can integrate with. Popular gateways include Authorize.Net, PayPal, and Stripe.

Steps to Build a Payment Gateway

 Building your own payment gateway may seem daunting, but can be broken down into several key steps:

Choose Your Platform

After selecting the appropriate platform and language for building your payment gateway, the next step involves understanding the specific requirements and functionalities needed to support seamless transactions. Some key considerations include:

  • Security - Implementing robust security measures is paramount to safeguard sensitive financial information. Ensure compliance with industry standards such as PCI DSS (Payment Card Industry Data Security Standard) to protect against data breaches and fraud.
  • Payment Processing Integration - Integrate with various payment processors and acquirers to support a wide range of payment methods, including credit cards, debit cards, digital wallets, and bank transfers. Compatibility with multiple processors allows for flexibility and choice for both merchants and customers.
  • User Experience - Design a user-friendly interface for both merchants and customers to easily navigate and complete transactions. Provide features such as one-click checkout, saved payment methods, and seamless redirection to payment pages to enhance the user experience and minimize friction during the payment process.
  • Error Handling and Logging - Implement robust error handling mechanisms to detect and handle errors gracefully, ensuring that users are informed of any issues encountered during payment processing. Additionally, maintain comprehensive logs to track transaction histories and troubleshoot any discrepancies or issues that may arise.
  • Scalability and Performance - Build a scalable and high-performance architecture capable of handling varying transaction volumes and spikes in traffic. Utilize cloud-based solutions and distributed architectures to ensure scalability and reliability, especially during peak times.
  • Compliance and Regulation - Stay informed about evolving regulatory requirements and compliance standards in the payment industry. Adhere to legal and regulatory frameworks such as GDPR (General Data Protection Regulation) and PSD2 (Payment Services Directive 2) to maintain compliance and protect customer data.
  • Testing and Quality Assurance - Conduct thorough testing and quality assurance processes to identify and resolve any bugs or issues before deploying the payment gateway into production. Perform unit testing, integration testing, and end-to-end testing to validate functionality and ensure a smooth user experience by conducting usability testing.

By considering these factors and incorporating them into the development process, you can build a robust and reliable payment gateway that meets the needs of both merchants and customers. We will delve deeper into each of these aspects in the following sections to provide comprehensive guidance on building a successful payment gateway.

Integrate a Payment Processor API

Once you have selected the appropriate platform and language for building your payment gateway, the next crucial step is to integrate an API from a reliable payment processor such as Stripe, Braintree, Adyen, or PayPal. These payment processors offer comprehensive APIs that handle payment processing and merchant accounts, providing secure and efficient solutions for handling transactions.

Integrating the payment processor's API into your payment gateway allows you to leverage their infrastructure and expertise in handling payment transactions securely. This API facilitates communication between your application and the payment processor's servers, enabling seamless processing of payments, authorization of transactions, and management of merchant accounts.

When selecting a payment processor and integrating their API, consider factors such as:
  • Security - Ensure that the payment processor complies with industry security standards such as PCI DSS (Payment Card Industry Data Security Standard) to protect sensitive payment data.
  • Features and Functionality - Evaluate the features and functionality offered by the payment processor's API, including support for various payment methods, currency conversion, recurring payments, and fraud detection.
  • Documentation and Support - Choose a payment processor that provides comprehensive documentation, developer resources, and responsive support to assist you during the integration process and troubleshoot any issues that may arise.
  • Pricing and Fees - Understand the pricing structure and fees associated with using the payment processor's services, including transaction fees, monthly subscriptions, and additional charges for premium features or services.

By integrating the API from a reputable payment processor into your payment gateway, you can provide merchants with a secure and reliable payment processing solution that meets their needs and ensures a seamless checkout experience for customers. We will delve deeper into the integration process and best practices for working with payment processor APIs in the following sections. 

Build the Merchant Interface

With the backend payment processing implemented, you can focus on building the merchant-facing interface. This allows merchants to access payment reports and handle refunds.

Use a web framework like React to build an intuitive dashboard with transaction filtering, reports, profile management, and more. 

Test Extensively

Rigorously test the payment gateway before launch. Verify form validation, confirm successful payments, run load tests, check error handling, and more.

Fix any issues discovered during testing to ensure a smooth customer experience.

Go Live

Once thoroughly tested, you're ready to launch your payment gateway! Start off with a small set of beta testers before opening access more broadly.

Monitor performance and watch for any issues reported by merchants. Keep improving the gateway with updates and new features.

With careful planning and rigorous testing, you can build and deploy your own payment gateway to power your platform's payments.

Compliance Considerations

Operating a payment gateway comes with important compliance considerations to ensure security and build trust with customers. The primary compliance standard for the payments industry is the Payment Card Industry Data Security Standard (PCI DSS). This provides a baseline of technical and operational requirements to protect cardholder data.

Some key PCI DSS requirements include:

  • Encrypting cardholder data during transmission over public networks using strong cryptography. This prevents sensitive information from being intercepted by malicious actors.
  • Storing cardholder data securely through encryption, tokenization, or other controls. This protects data at rest from compromise.
  • Limiting access to systems with cardholder data on a need-to-know basis. This reduces the risk of data exposure through unauthorized access.
  • Maintaining secure networks with firewalls, anti-malware, and vulnerability management programs. This hardens the environment against intrusions.
  • Tracking and monitoring access to networks and card data. This enables visibility into potential issues.
  • Testing security systems and processes to identify weaknesses. This verifies the effectiveness of controls.

Besides PCI DSS, payment gateways may also need to comply with additional standards like PA-DSS for payment software developers or be certified by card brands. Staying current on evolving regulations is also important.

Ongoing compliance helps build trust that a payment gateway takes data security seriously. It also reduces risk for the merchant and provider. With robust controls and processes, customers can feel confident their information is protected when making transactions through the gateway.

Pricing Models 

When building your own payment gateway, one of the most important considerations is how you will charge merchants for using your service. There are a few common pricing models that payment gateways use:

Transaction Fees

The prevalent pricing model involves levying a modest percentage fee on every transaction facilitated through your gateway, commonly falling within the range of 2-3%. Transaction fees offer the benefit of aligning your revenue with the merchant's payment volume, allowing for scalable earnings as transaction volumes increase. However, it's worth noting that these fees may appear relatively high compared to competitors when analyzed on a per-transaction basis.

Monthly Fees 

Another approach is to charge merchants a flat monthly fee to use your gateway. This could be a simple flat fee like $25/month or tiered plans based on features and transaction volume. The benefit of monthly fees is predictable recurring revenue. The risk is merchants could get upset if their transaction volume is low or highly variable each month.

Setup Costs 

Some gateways also charge an initial setup fee when onboarding new merchants. This could be a one-time $200 fee to cover the administrative costs of establishing a new account. The advantage is additional upfront revenue. The disadvantage is it creates a barrier to new customer acquisition.

The best pricing often combines elements of transaction fees, monthly fees, and setup costs. Try to find the right balance for predictable revenue while keeping costs competitive. Test different price points with early customers to find the optimal structure.

Security Best Practices for Payment Gateways

Keeping customer data and financial information safe and secure should be the top priority for any payment gateway. Here are some of the top security best practices to follow:

  • Use HTTPS on your website and all endpoints that handle sensitive data. HTTPS encrypts data in transit, preventing man-in-the-middle attacks. Only transmit cardholder data over HTTPS.
  • Tokenize card numbers as soon as possible. Tokenization replaces card numbers with random tokens, so the actual card data is never stored. This limits your PCI compliance scope significantly.
  • Implement fraud detection and prevention measures like AVS, CVV, address verification, IP geolocation, etc. Actively monitor for suspicious activity patterns.
  • Conduct regular penetration testing and security audits. Hire third-party security experts to find vulnerabilities before attackers do.
  • Maintain secure backups of transaction records and audit logs. Backups allow you to restore data if needed.
  • Enforce data access controls and the principle of least privilege. Only allow the minimum access staff need to do their jobs.
  • Use end-to-end encryption whenever possible. Encrypt data before it ever reaches your servers.
  • Maintain physical security of your data centers and servers. Use video surveillance, security guards, and strict access controls.
  • Keep all software like OS, firewalls, and databases fully updated and patched. Apply security updates promptly.
  • Monitor networks for anomalies, intrusion attempts, and DDoS attacks. Use IDS/IPS systems and active monitoring.
  • Develop an incident response plan for security breaches or attacks. Know how to respond quickly to limit damage.

Following security best practices requires constant vigilance, but is crucial for maintaining a robust, trusted payment gateway.

4 Benefits of a payment gateway

Payment gateways offer numerous benefits, including but not limited to:

Better security

As previously stated, several verification steps occur during the payment procedure to verify that the individual making the purchase is the rightful cardholder. Additionally, payment gateways must adhere to PCI DSS compliance standards, ensuring the protection of cardholder data and enhancing fraud prevention measures. 

Also, payment gateways typically offer supplementary features such as tokenization, Address Verification Service, and risk management solutions (such as velocity checks, transaction counts, amount thresholds, device fingerprinting, negative database data, etc.).

Better experiences

Having a payment gateway enables your customers to make purchases conveniently anytime and anywhere. 

Additionally, customers have the option to securely store their payment details for future transactions with a merchant through tokenization. By offering a seamless payment experience, you can foster brand loyalty and incentivize repeat purchases.

Enter new markets

Many payment gateways provide multi-currency support and the capability to integrate with various local and global payment methods, offering customers flexibility in their payment options. For example, emerchantpay offers access to more than 80 global payment methods such as Apple Pay, Google Pay™, PayPal, SEPA payment schemes, and paysafecard. 

This range of choices enables businesses to expand globally and tailor their payment gateway to suit the specific payment preferences of their customers.

Checkout options 

Easy Integration for a Seamless Checkout

eMerchantPay makes it simple to add secure payment processing to your website. We offer several integration methods to fit your needs:

  • Hosted Payment Page: Customers securely complete their purchase on a branded eMerchantPay page.
  • Server-to-Server Integration: This secure method keeps your customer data on your server for maximum control.
  • Client-Side Encryption: Encrypts customer information on your website before sending it to eMerchantPay for added security.
  • Shopping Cart Plugins: We integrate seamlessly with popular eCommerce platforms for a smooth checkout experience.

No matter your setup, eMerchantPay can customize the payment flow to match your business requirements.


  • Clearer Headline: The title highlights the benefit for businesses.
  • Simpler Language: Technical terms are replaced with easier-to-understand language.
  • Benefit-focused: The text emphasizes how each integration method benefits businesses.
  • Conciseness: Unnecessary phrases are removed for a tighter message.

Most popular posts

Join over 98,542 people who already subscribed.

Follow us on Google News



Related Posts



No comments made yet. Be the first to submit a comment
Monday, 15 April 2024
Table of contents
Download as PDF

Ready to learn more? 👍

One platform to optimize, manage and track all of your teams. Your new digital workplace is a click away. 🚀

I'm particularly interested in an intranet for