Payment Gateway Testing: Use Cases, Test Cases, 2025-Fit Solutions

Payment gateway testing separates companies that thrive from those that crumble under pressure — this guide will show you build a system that is close to bulletproof.

But for now, let’s run a scenario.

A customer tries to buy your product at 11:47 PM on Black Friday. They’ve filled their cart, entered their details, clicked “Pay Now”… and your payment gateway crashes.

Now multiply that scenario by thousands of transactions daily. Welcome to the high-stakes world of payment gateway testing, where a single bug can cost millions and a security flaw can destroy years of trust overnight.

In 2024 alone, payment failures drained $1.86 trillion from global e-commerce revenue.

You need the invisible infrastructure that powers modern business. Every swipe, tap, and click relies on payment systems that must perform flawlessly under crushing pressure, evolving threats, and endless complexity.

Key Points Summary

The essential takeaways every decision-maker needs to know about payment gateway testing:

✅ Payment gateway testing reduces business risk. Comprehensive testing prevents revenue loss from failed transactions and security breaches that cost companies an average of $4.88 million.

✅ Automation covers 90% of testing needs. Strategic automation focuses on regression, API, and performance testing while manual testing handles complex scenarios and edge cases.

✅ Security testing is non-negotiable. With payment fraud reaching $32 billion annually, robust security testing protects customer data and business reputation through PCI DSS compliance.

✅ Real device testing provides superior results. Testing on physical devices identifies 60% more issues than emulators or device farms, especially for mobile payment integrations.

✅ Seven core test cases are essential. Credit card authorization, payment confirmation, connection stability, exchange rates, negative scenarios, security validation, and refund processing.

✅ Integration testing ensures seamless operation. Payment gateways must work flawlessly with banks, processors, and third-party services like Apple Pay and digital wallets.

✅ Performance testing prevents revenue loss. Payment systems must handle traffic spikes without failures during peak periods like Black Friday.

✅ Compliance testing reduces legal risk. Payment systems must meet PCI DSS, GDPR, and regional financial regulations to avoid costly penalties.

✅ ROI is measurable. Companies achieve 40% fewer transaction failures, 85% improved security posture, and 75% faster testing cycles with comprehensive payment testing.

✅ Real-world testing is crucial. Sandbox environments handle 90% of scenarios, but real payment testing with actual cards validates critical user journeys.

What Are Payment Systems and Payment Gateways?

Summary: Payment gateways handle transaction authorization while payment systems process complete payment workflows. Understanding this distinction is crucial for effective testing strategies.

Payment gateways and payment systems serve different but interconnected roles in digital transactions:

Payment Gateway: Acts as the secure bridge between customers, merchants, and banks. It handles authorization, encryption, and transaction routing. Think of it as the digital equivalent of a POS terminal that focuses on front-end user interactions.

Payment System (Payment Processor): Manages the complete transaction lifecycle including funds verification, fraud detection, settlement, and chargeback handling. It performs the heavy lifting behind every successful payment.

Most payment gateway testing projects examine both components since they work together to process transactions. However, testing scope depends on your specific implementation – sometimes you’ll test payment gateway integration with third-party processors, other times you’ll need comprehensive end-to-end testing.

Why Payment Gateway Testing Is Critical for Business Success

Summary: “U.S. $118.5 billion. That is how much failed payments are estimated to cost the global economy each year,” as per LexisNexis research. Payment testing prevents revenue loss, ensures regulatory compliance, and protects customer data. 

Testing is an integral part of any software development process, and one cannot be imagined without the other.

Testing ensures the spotless functionality, utmost stability, complete security, and engaging UX of a software product. However, there are product types where testing is even more indispensable, and payment systems definitely belong on that list. Here are just a few reasons why payments testing is absolutely crucial for your project:

Financial protection. Payment failures cost e-commerce businesses $1.86 trillion globally in 2024. Comprehensive testing reduces transaction failures by 40% and increases successful payment completion rates.

Security compliance. With cybercrime costs reaching $10.5 trillion annually, robust payment gateway security testing protects sensitive financial data and maintains PCI DSS compliance.

Words by

Michael Tomara, QA Lead, TestFort

“Since security testing is particularly vital for payment products, and since security testing always benefits from being automated, we can also say that payment gateway automation testing is well-suited for white-box and grey-box testing. When testers know how the system works and are familiar with the code, their testing approach will generate better results and positively impact the product’s security.”

User retention. 67% of users abandon purchases after encountering payment issues. Thorough payment app testing ensures smooth checkout experiences that drive customer loyalty.

Regulatory adherence. Payment systems must comply with AML, PCI DSS, GDPR, and local financial regulations. Non-compliance penalties can reach millions of dollars.

Scalability assurance. Black Friday 2024 saw payment volumes increase 340% over average days. Performance testing ensures your payment gateway handles traffic spikes without failures.

Learn how we resolved 672 payment bugs with 80%+ success rate across 12 devices for a leading UK fintech.

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Essential Payment Gateway Test Cases: What Needs to Be Tested

Summary: The exact set of test cases for payment gateway testing depends on project requirements, but certain core scenarios must be tested across all payment solutions.

Having provided testing across dozens of payment systems, we have a firm grasp of what teams must test in payment solutions. Here are the most common sample payment gateway test cases:

Core payment test cases

Credit card authorization testing

• System must verify credit card details, currency, user location, and other parameters to ensure payment authorization by the bank;

✅ Green Flag: 99.9% authorization success rate for valid cards across all card types;

• ❌ Red Flag: Authorization failures for valid credit and debit card payments;
• Critical Question: Does your system handle authorization for all major card networks?
• Action Item: Test authorization across diverse payment methods and international markets;

Payment confirmation validation

• Ensure payment processes correctly and users receive timely confirmation while banks get payment confirmation on their end;
• ✅ Green Flag: Real-time payment confirmation with detailed transaction information;
• ❌ Red Flag: Delayed confirmations or missing payment status updates;
• Must-Verify: Confirmation delivery across all payment types and user scenarios.

Connection stability testing

• Stable internet connection is integral for correct payment solution operation;
• Test different connection conditions and interruption scenarios;
• ✅ Green Flag: Graceful handling of network issues with clear user guidance and automatic recovery;
• ❌ Red Flag: Payment failures without proper error messaging or recovery options;
• Key Question: Does the payment process resume correctly after connection restoration?
• Test Scenarios: Network interruptions, slow connections, timeout handling.

Exchange rate accuracy testing

• For global products, ensure payment gateway uses correct exchange rates for all currency pairs
• Verify swift exchange rate updates when rates change
• ✅ Green Flag: Real-time rate updates with accuracy within 0.1% of market rates
• ❌ Red Flag: Outdated exchange rates or slow rate update processes
• Action Required: Implement automated rate validation for international transactions

Advanced payment scenarios

Negative scenario testing

• Account for both common and unlikely scenarios where online payments fail
• Oversee system reactions to payment failures and user options for aborting or resuming transactions
• ✅ Green Flag: Clear error messages with actionable resolution steps for users
• ❌ Red Flag: Generic error messages that don’t help users understand or resolve issues
• Critical Test: Payment failure recovery across different payment methods

Security validation testing

• Most important aspect of testing payment solutions for application security
• Automated penetration testing and security scanning cover maximum scenarios
• Manual security checks for password rules, username strength, fail-open authorization, input validation, trust relationships

✅ Green Flag: Zero critical security vulnerabilities with regular security assessments

❌ Red Flag: Manual security testing only or outdated security validation

Security Practice: Enterprise password managers for secure credential handling during testing

Compliance Focus: Payment card industry data security standard adherence

Refund processing testing

• Refunds are common in online transactions and can be requested months after purchase
• Ensure relevant data storage security for extended periods to make refunds possible
• Verify smooth refund operation for all parties: customer, seller, and bank
• ✅ Green Flag: 100% successful refund processing within defined timeframes
• ❌ Red Flag: Refund failures or data inconsistencies affecting long-term transactions
• Action Item: Test refund workflows across all supported payment types

Testing implementation guidelines

Test case development

• ✅ Green Flag: Comprehensive test cases cover all payment gateway functionality and edge cases
• ❌ Red Flag: Test cases focus only on happy path scenarios
• Best Practice: Include testing for diverse payment methods, operating systems, and user scenarios

Testing environment setup

• Use virtual card simulations for development testing
• Implement real payment testing for production validation
• Maintain secure testing environments that mirror production configurations

Data security in testing

• Never use real customer payment data for testing purposes
• Implement secure test data management practices
• Ensure GDPR and privacy compliance in testing processes

Comprehensive payment testing strategy

Payment gateway testing ensures your system delivers secure, reliable transactions across all payment types and user scenarios. Systematic testing covers functional validation, security compliance, performance optimization, and user experience enhancement.

Success indicators:

• Automated testing covers 90% of payment functionality
• Zero critical security vulnerabilities maintained
• 99.9% payment processing reliability achieved
• Sub-3-second transaction completion times
• Comprehensive test coverage across diverse payment methods

Effective payment testing combines automation for efficiency with manual testing for complex scenarios. Whether testing Apple Pay integration, credit card processing, or international payment flows, thorough test case coverage protects revenue and builds customer trust.

Investment in comprehensive payment solution testing delivers measurable ROI through reduced failures, improved security posture, and enhanced user experience that drives business growth.

Advanced Payment Gateway Testing Techniques

Modern payment testing relies on specialized testing types that go beyond basic functionality checks. These advanced techniques ensure your payment gateway to ensure flawless operation across all payment options and complex integration scenarios.

Real-device testing for payment applications

Testing on 250+ real devices provides critical insights that emulators miss:

Advantages of real device testing:

• Hardware-specific payment integrations (NFC, biometric authentication)
• Real-world network conditions and interruptions
• Actual device performance under memory constraints
• True user experience validation

Device coverage strategy:

• Popular smartphones (iOS/Android) across price ranges
• Tablets for B2B payment applications
• Various OS versions and browser combinations
• Different screen sizes and resolutions

“Hardware-software integration testing requires real devices to validate NFC payment processing, biometric authentication, and device-specific performance characteristics. Emulators simply cannot replicate the complexity of actual payment hardware interactions.” – Michael Tomara, QA Lead

API-first payment testing approach

Modern payment systems rely heavily on APIs, making API testing crucial:

API testing focus areas:

• Request/response validation
• Error handling and status codes
• Authentication and authorization
• Rate limiting and throttling
• Data format and schema validation

Check payment gateway security: Advanced techniques

Comprehensive security testing methods:

• Penetration testing by certified security experts
• Vulnerability scanning with OWASP Top 10 focus
• Social engineering simulations
• Data encryption verification
• Access control testing

“How do I know if my payment gateway is secure? Look for PCI DSS compliance, regular penetration testing, encryption at rest and in transit, and comprehensive access controls. These are non-negotiable security foundations.” – Michael Tomara, QA Lead

Digital Payments Testing: Future Trends

Emerging technologies like AI-powered fraud detection, cryptocurrency integration, and biometric authentication require evolved testing strategies for 2025 and beyond. These trends represent the future of secure, efficient payment processing. 

Companies that adapt their testing strategies early gain competitive advantages through faster innovation cycles, better security posture, and superior user experiences.

AI-powered testing: Machine learning algorithms now identify 95% of testing scenarios automatically, reducing manual test case creation by 80%.

Cryptocurrency testing: Digital currency integration requires specialized testing for:

• Blockchain transaction validation
• Smart contract functionality
• Wallet integration testing
• Regulatory compliance for digital assets

Biometric authentication testing: Fingerprint, facial recognition, and voice authentication require:

• Multi-modal biometric testing
• Spoofing resistance validation
• Accessibility compliance
• Performance optimization

Real-time analytics: Advanced testing now provides:

• Live payment performance monitoring
• Predictive failure analysis
• User behavior insights
• Automated test optimization

The investment in advanced testing capabilities today determines tomorrow’s market position.

Automated Testing of Payment Systems

Test automation is a perfect fit for payment solution testing. It helps get the most reliable results of testing and avoid many of the quality-related risks while saving time and resources compared to manual testing. But what should you automate in the first place for a payment testing project? Here are the testing activities that make particular sense to automate:

Functional testing

Checking the payment gateway functionality, transactions, card statements, payment history, etc.

Green flags

• All payment methods (credit card, debit card, Apple Pay, digital payment methods) work seamlessly
• Transaction histories are accurate and accessible
• Card details verification processes function correctly

Red flags

• Payment processes fail silently without error messages
• Inconsistent behavior across different payment methods
• Missing transaction confirmations or receipts

To-do checklist

• Test all supported payment methods (credit and debit card payments, virtual card simulations)
• Verify transaction logging and history accuracy
• Validate payment confirmation workflows
• Test refund processing functionality

Regression testing

Making sure the recent changes to the code did not negatively affect the application as a whole.

Green flags

• Automated regression test suites run after every code deployment
• Critical payment flows remain functional after updates
• Performance metrics stay within acceptable ranges

Red flags

• New features break existing payment functionality
• Performance degradation after updates
• Security vulnerabilities introduced in recent changes

To-do checklist

• Establish automated regression testing pipelines
• Create comprehensive test case coverage for core payment flows
• Set up performance benchmarking for regression detection
• Schedule regular regression testing cycles

API testing

Testing the APIs integrated into the end product, both on their own and as part of a larger system.

Green flags

• API responses are consistent and properly formatted
• Payment gateway integration testing covers all third-party payment services
• Error handling for API failures is robust

Red flags

• API timeouts cause payment failures
• Inconsistent data formats between different payment gateways
• Missing error handling for API edge cases

To-do checklist

• Test API endpoints for all payment gateways (PayPal, etc.)
• Validate API response formats and error codes
• Implement timeout and retry logic testing
• Verify API authentication and authorization

Performance, load and stress testing

Ensuring the payment application can withstand any number of users and transactions.

Green flags

• System can handle peak transaction volumes
• Response times remain acceptable under load
• Auto-scaling mechanisms work effectively

Red flags

• Payment processing slows down during high traffic
• System crashes under stress conditions
• Memory leaks or resource exhaustion issues

To-do checklist

• Define performance benchmarks for payment processing
• Test app performance across diverse payment methods
• Simulate peak traffic scenarios
• Monitor system resources during load testing

Security testing

Performing comprehensive checks to make sure the app is impenetrable for those who want to interfere with data.

Green flags

• Compliance with payment card industry data security standard
• Regular penetration testing and vulnerability assessments
• Secure handling of credit card numbers and sensitive data

Red flags

• Unencrypted transmission of payment data
• Weak authentication mechanisms
• Non-compliance with PCI DSS requirements

To-do checklist

• Implement comprehensive compliance testing
• Conduct regular security audits
• Test encryption of payment data in transit and at rest
• Validate secure payment processing workflows

The success of payment gateway automation testing depends on several factors: the skills and experience of the team, the match between the project specifics and its goals, and the correctly selected stack of tools and frameworks.

Words by

Taras Oleksyn, Multi-Domain AQA Expert

“For payment applications, security threats are constantly evolving, and the attacks are getting more intricate and more daring. From Man in the Middle and cross-site scripting attacks to site injections and social engineering, automated security testing constantly has to deal with increasingly complex tasks. And that includes testing not only the payment application and the software it’s implemented with, but also the company’s software infrastructure that may not be directly linked to the payment solution but can still pose security risks to the whole ecosystem.”

The choice of tools to use on the project is directly linked to the tech stack used to create the product. For example, when it comes to API testing, there are specific tools for each programming language used to create the API: there is REST Assured for Java, Requests module for Python, and so on. At the end of the day, the team uses a set of metrics to determine whether the setup is successful and whether the automation efforts pay off, or whether there are additional steps that need to be taken.

See why leading fintech companies trust TestFort for payment gateway testing, security validation, and compliance.

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Test Cases for Payment System Testing: What Needs to Be Tested

Summary: Payment gateway testing requires covering seven core areas:

• credit card authorization,
• payment confirmation,
• connection checks,
• exchange rates, negative scenarios,
• security checks, and refund processing.

These test cases ensure your payment system works reliably and securely for customers.

The exact set of payment gateway test cases for a payment gateway testing project will always depend on the project requirements, the specifics of the product, and the goals that need to be achieved. Still, having provided testing across dozens of payment systems and other related products, we have a firm grasp of what the team must test in a payment solution and what this segment of testing covers. Here are some of the most common sample payment gateway test cases to get you started:

1. Credit card authorization. Here, the system must take certain parameters, such as credit card details, currency, user’s location, and others, to verify that the payment is authorized by the bank and allowed to proceed.
   
2. Payment confirmation. Once the payment is processed, the testing team needs to ensure that it proceeds correctly and that the user receives a timely confirmation of the payment, while the bank or card issuing company also gets a payment confirmation on their end.
   
3. Connection check. A stable, uninterrupted internet connection is integral for the correct operation of the payment solution. For this stage of testing, the team will simulate different conditions to see how they affect the connection, and how the interruptions in the connection, in turn, affect the payment process: for example, whether the user gets a corresponding error message and whether the process resumes after the connection is restored.
   
4. Exchange rates. When the product is going to be available globally, one of the key tasks for the testing team is to ensure that the payment gateway uses correct exchange rates for all currency pairs. The exchange rates also need to be updated swiftly when they change, which is why the testing procedure should also include verifying how quickly it happens.
   
5. Negative scenarios. A significant portion of payment gateway testing ensures that the payment is completed successfully. However, that is not always the case, and an online payment can fail for a myriad of reasons. The team’s job is to account for both common and unlikely scenarios, overseeing the way the system reacts to payment failures and what options the user has for aborting or resuming the transaction.
   
6. Security checks. One of the most important things to check payment gateway for is the security of the application. Some security tests, like penetration testing and security scanning, need to be automated to cover as many scenarios as possible, but it is also possible to do manual security checks. For example, the team may test password rules, password and username strength, fail-open authorization, input validation, trust relationships, and more. Many teams use enterprise password managers to securely handle credentials, minimizing access risks during testing.
   
7. Refund processing. Refunds are a common byproduct of online transactions, and depending on the merchant’s policy, the refund can be requested and issued months after the purchase. This means the team has to make sure that all relevant data is stored securely for an extended period of time to make the refund possible, and that the refund itself works smoothly for all parties, including the customer, the seller, and the bank.
   

Building a robust test case foundation

The seven core test case categories outlined above form the essential foundation for any comprehensive payment gateway testing strategy and serve as the cornerstone of this ultimate guide to payment gateway testing. While each organization’s specific requirements will dictate the exact scope and depth of testing, these fundamental areas represent the non-negotiable elements that determine whether a payment processing system will succeed in real-world conditions across e-commerce and online businesses.

Comprehensive testing ecosystem. Payment gateway testing services must address multiple different types of testing that work interconnectedly. Testing involves verifying that payment gateway security testing integrates seamlessly with credit card authorization processes, while compatibility testing across various operating systems directly impacts the overall payment experience.

Testing includes usability testing, accessibility testing, and localization testing to ensure optimal user experience regardless of how customers access your website or application.

Case in point:

Famous European neobank — mobile banking service provider — required comprehensive testing of their mobile POS system before global expansion.

Our team conducted hardware-software integration testing across 12 devices, including iOS, Android, iPad mini, and iPad Pro variants.

This real-device testing approach identified critical compatibility issues that led to an app rating improvement from 4.2 to 4.7 stars and an 87% boost in mobile conversions. The comprehensive device coverage revealed firmware update conflicts and SDK compatibility issues that would have been missed in emulated environments.

Diverse payment method coverage. Modern payment testing services must accommodate various types of payment methods and types of payment gateway configurations. Whether testing involves a hosted payment solution, integrated payment gateways include PayPal, Cash App, or custom implementations, each test case example demonstrates how testing the payment flow requires specialized approaches.

Payment app testing services and payment software testing services must ensure that every gateway processes transactions reliably across diverse payment ecosystems.

Strategic risk mitigation. Testing helps businesses proactively identify issues before they impact customers. Payment gateway testing verifies that each payment gateway is secure and delivers insights into the payment process that can prevent costly failures.

When you run the test scenarios systematically, testing can provide comprehensive coverage that protects against revenue loss, compliance violations, and damaged customer trust in the competitive payment domain.

Scalable quality framework. These test cases for payment gateway systems provide a scalable framework adaptable to evolving payment technologies. Whether enhancing app performance for diverse international markets, integrating new types of payment methods, or expanding testing environments, this foundation ensures that testing involves verifying critical functionality throughout system evolution.

Payment gateway testing ensures that testing purposes align with business objectives while maintaining the highest quality standards.

Business-critical excellence: Ultimately, well-prepared test cases for a payment gateway serve as the guardian of your payment system’s reliability and your business’s reputation. This guide to payment gateway testing demonstrates how testing involves comprehensive evaluation of every aspect that affects payment experience.

Testing can provide the confidence that when customers choose to trust you with their financial transactions — whether through traditional credit card processing or modern digital wallets — your payment gateway ensures secure, smooth, and dependable service delivery.

The investment in comprehensive payment testing services pays dividends through reduced support costs, improved customer satisfaction, regulatory compliance, and sustained business growth built on a foundation of payment system excellence that serves online businesses across all industries and markets.

See how we delivered 14% satisfaction boost and 25% fewer bugs for a Middle East banking giant in just 4 months.

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How to Test Payment Systems and Payment Gateways

Summary: Eight steps for testing payment system and payment gateways proved by over a decade of Quality Assurancep projects in Fintech and eCommerce. 

Step #1. Determine the scope

Step #2. Create use cases

Step #3. Prepare test cases

Step #4. Get the infrastructure ready

Step #5. Run the tests

Step #6. Observe the outcomes

Step #7. Document the results

Step #8. Create reports and analytics

Continue reading for a detailed description of each step, and see how it applies and may be adopted to your project. 

Having delivered payment gateway testing services for over 15 years and for dozens of clients, we have time and time again come to realize that precise planning is just as important for the success of the project as making immediate decisions based on the project specifics. This is why, while we always leave room for adjustments, our procedure for testing includes certain steps and activities we cannot do without. Here is how we approach testing payment applications.

Step #1. Determine the scope

Together with the project stakeholders and developers, the testing team will determine the scope of testing, e.g. what needs to be tested and on what scale. Taking the time to complete this step will save the team from wasting valuable resources and will help keep the testing process streamlined.

Step #2. Create use cases

This is the stage where the testing team, along with business analysts and other specialists, work to create user personas and use cases for the application. For this stage to work properly, it is integral for the team to account for the whole variety of users and their needs, creating a diverse range of user personas, who, in turn, will influence the number and variability of use cases: the more potential scenarios are covered during testing, the more successful the release is going to be.

Step #3. Prepare test cases

Using the information obtained at the two previous stages, this is where the testing team will create detailed payment gateway test cases to be executed later. Depending on the specifics of the product, the test cases will be focused on functionality, security, compatibility, performance, accessibility, and other parameters of a well-tested payment gateway. The in-depth description of the steps and conditions contained in test cases for payment gateway testing is crucial for continuity in case another testing team has to take over or the developers need to replicate the event.

Step #4. Get the infrastructure ready

Testing payment systems requires the use of specific infrastructure, which may include various hardware and software, as well as testing environments. It is essential to test payment gateway on different mobile and desktop devices, as well as on different operating systems and in different browsers. And while there is an option of using device emulators and farms, at the end of the day, nothing beats the efficiency and reliability of testing on real devices — the way we do it at TestFort.

Step #5. Run the tests

This is an integral part of the testing process where the team goes over the test cases one by one, executing the tests and noting whether they passed or failed. This process should run according to the predefined plan, and the team should watch out for any test runs that produce unexpected results. In most cases, this stage will include initiating a transaction based on a specific set of conditions, entering payment details, and completing the payment, or using different techniques to prevent it from being completed.

Step #6. Observe the outcomes

A vital part of testing a payment gateway is evaluating the outcome of the test run. Was the test successful? Did it happen the way it was described in the test case? What did the process feel like to an average user? Were the transaction stages and the accompanying system messages easy to understand and informative? Examining the payment process from the standpoint of a user is a highly useful activity that adds value to the testing process.

Step #7. Document the results

Documentation is a sometimes overlooked aspect of testing, but we cannot stress the importance of documentation enough. Documenting the process and especially the results makes them more tangible and easily accessible for the team, both the people currently involved in the project and the people who will be involved in it at later stages. Documentation can also be used by developers and project stakeholders, so this is not a step that can be omitted or taken lightly.

Step #8. Create reports and analytics

Once the testing team has enough data, they should turn it into reports and use various tools, including AI-based ones, to describe the state of the application, its functionality, stability, performance, usability, and other essential parameters. Detailed reports and robust analytics will give the developers and other stakeholders a complete picture of where the product’s quality stands at the moment and what can be done to improve it.

Payment testing isn’t complete without POS validation.

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The Importance of Testing on Real Devices

Here at TestFort, we pride ourselves on testing software on physical devices, and that includes payment solution testing. Our procedure for payment system testing involves checking the product on 250+ real devices ranging from entry-level smartphones and tablets to flagship devices, and that helps us ensure a few vital outcomes:

Testing the solution on different combinations of devices, versions of operating systems, and settings allows us to cover hundreds of target device setups, making the system’s behavior more predictable regardless of the platform or the user’s preferences in setting up their devices.

Using physical devices for testing a payment processing system and other types of payment solutions allows us to utilize all the software and hardware infrastructure available on the device, including various sensors, biometric authentication solutions, and built-in payment systems like Google Pay and Apple Pay.

Employing a fleet of real devices is the only real way to check payment gateway and see how the application being tested is impacted by the variety of events that take place on a mobile device, such as notifications, calls, system alerts, error messages, network and internet connection issues, and applications running in the background.

Challenges of Testing Payment Gateways

Payment gateway testing helps businesses make sure their software is release-ready and able to compete with the market leaders. And the payment system QA field has come a long way since its inception, introducing different types of testing, techniques, tools, and best practices to make the process more effective. Still, like any QA activity, testing payment systems has its challenges, and here are the most common ones.

Increasing complexity of systems

Online payment systems are getting more and more elaborate and include more and more cutting-edge functionality. In addition to testing credit and debit card payments, testing teams now also have to focus on cryptocurrency and other advanced technologies as well. Plus, as scammers are getting more creative with their attempts to steal sensitive information, testers should also get more creative with their digital payments testing approaches.

Variety of integrations

In the online payment landscape these days, there is no shortage of range. There are dozens of diverse payment methods available, and those are integrated with an even bigger variety of banking, financial, and eCommerce solutions. As a result, testers often have to deal not just with the payment gateway itself, but also with the way it operates with other systems, and the sheer number of possible combinations can be overwhelming for a team with limited resources.

Words by

Igor Kovalenko, QA Lead and Mentor, TestFort

“On one hand, one of the ways to measure the payment system’s success is by the number of its integrations into other systems. On the other hand, this creates an additional challenge for testing teams, who have to test more and more combinations of the payment gateway with other solutions.

When the team does not have enough resources to cover the increasing testing needs, a good solution to the problem can be to automate as much testing as possible, given that it adds value and makes sense in your context.”

Intricate regulatory requirements

As eCommerce and online payments are becoming more of a mainstay in our lives, governments around the world are making an effort to control the industry and prevent fraud and user data getting mishandled. There are numerous regulations specific to the financial domain in most foreign markets, which means the more locations you want to release your product in, the more regulatory requirements it will need to comply with, and the complexity of the regulations is a challenge on its own.

Outdated testing infrastructure

Testing advanced software solutions requires the use of equally advanced testing infrastructure. Unfortunately, that is not always the case, particularly when the company is trying to keep the testing operations in-house. 

In that case, the testing process may not end up meeting all the project goals. Plus, the cost of testing may increase because the outdated infrastructure requires more time and effort to complete a simple task. Entrusting testing to a trusted provider with all the necessary infrastructure is a great way to alleviate those risks.

FAQ:

How do you test a payment gateway?

Testing a payment gateway means verifying the entire transaction flow — from card entry to final confirmation — under both normal and edge conditions.
This includes:
– API interactions with payment processors and banks;
– 3D Secure, fraud protection, and encryption validation;
– Refunds, chargebacks, currency handling;
– UX during success, failure, or timeout scenarios.
Both automation and manual testing are usually required to cover all risks.

What are the requirements metrics of a payment system?

A reliable payment system must meet specific quality, performance, and compliance benchmarks — especially in production.
Some of the key metrics to monitor during testing include:
– Success rate of completed transactions;
– Response time from payment initiation to result;
– System uptime and behavior during failure;
– Data accuracy across all steps of the flow;
– Compliance coverage, e.g. PCI DSS, AML/CFT, PSD2, GDPR.
These metrics should be validated through load testing, integration tests, and continuous monitoring.

How to test payment gateway manually?

Manual testing is used to simulate realistic user behavior and explore less predictable conditions automation might miss.
It typically includes:
– Performing transactions with both valid and invalid payment data
– Checking UI behavior and messages for clarity and accuracy
– Testing slow networks, unexpected user actions, or session drops
– Verifying local currency display and input formatting
– Spot-checking fraud alerts or two-factor authentication logic
Manual regression testing is also helpful after hotfixes and new integrations.

How to test payment gateway integration?

Payment gateway integration testing focuses on the data exchange between your app and external payment services.
To validate it properly:
– Simulate real payments using sandbox accounts or test cards;
– Confirm correct request/response handling through APIs;
– Check webhook calls for delays, retries, or errors;
– Validate internal logs and ensure successful handoffs between systems.
Automating these checks allows quick feedback during development and CI/CD.

How do I know if my payment gateway is secure?

To know your payment gateway is secure, you need a combination of targeted testing, vulnerability scanning, and compliance review.
Make sure to include:
– Penetration tests against known attack types (e.g. XSS, MITM, brute force);
– Checks for tokenization and data encryption at rest/in transit;
– Authentication and session management validation;
– OWASP Top 10 and PCI DSS checklist coverage;
– Internal access control and audit trail verification.
Security testing should be ongoing — not a one-time task — and ideally validated by external experts.

Final Thoughts

Payment systems and payment gateways are one of those software types that are everywhere around us, even if we don’t always notice them. And even though there are a few great payment solutions in the market already, with the growing number of online transactions, there will always be room for more. At the same time, it’s important to remember that users are not going to have much patience for an application that is riddled with usability bugs or much trust for a product that has been involved in security-related controversies. Timely and all-encompassing software testing helps nip those risks in the bud, and we hope that our guide has made things clearer for you in this regard.