What is Interface Testing with Types, Examples, and Tools

May 10, 2024Ritika Kumari
What is Interface Testing with Types, Examples, and Tools

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An application is a collection of several components functioning together to meet user requirements. APIs, servers, web services, databases, and more are intertwined under one roof to build software that does what you want it to do. For instance, your favorite e-commerce store has UI elements, cart and Wishlist functionality, secure payment option, rewards, login, and many more systems running together to improve your shopping experience. These separate modules communicate through an interface. And for flawless interaction, Interface testing is critical because any type of error in the interface can lead to system issues.

Understandably, Interface testing is an essential part of your test planning that must not be skipped. And because it requires a clear knowledge of different components and the need to review data transfer between them, you would also need an elaborate guide on how to perform Interface Testing.

We bring that one guide to you.

What is Interface Testing?

Interface testing is a type of software testing that verifies the interaction between two separate systems of an application. It is a medium that helps components communicate with each other. Usually, it can be in the form of API, UI, servers, graphics, and more. It uses specific commands, messages, and data transfer techniques to act as a connection between the user and the application.

Keep in mind that Interface testing does not validate the functioning of a single component. It only checks if two interfacing systems communicate properly for the software to work as per requirements. If any conflict or issue arises during the testing phase, it is dealt with by the developers.

Advantages of Interface Testing

There are a few advantages of Interface testing:

  • An easy-to-understand and use UI decreases the learning for the users to use the application
  • Interface testing increases the application’s demand in the market due to it having a stable design and un-complex GUI
  • It helps get a grip on what users expect from the application and modify the interface according to that knowledge
  • Interface testing improves overall customer satisfaction and makes for an effective application with the potential to gather more users.

How to Perform Interface Testing?

Primarily, Interface testing is for two systems of an application that have connections with each other to ensure the proper functioning of the application. It consists of two major sections:

  • The interface between the web server and the application server
  • The interface between the application server and the database server

It is necessary to check for the interfaces mentioned above to :

  • That these servers are running properly
  • The servers have the right error handling capability, along with the option to return an error message for queries made by the application
  • If outcome is proper if/when the connection gets severed due to any problem

Types of Interface Testing with Examples

We know that Interface testing checks for connections between two systems in a software. And you can do that by performing various types of Interface testing that we have discussed below:

Workflow Testing

As per the name, Workflow testing checks for the end-to-end working of the application to validate proper data transfer. The goal is to ensure that the system functions as per the user expectations. Its purpose is to verify if the software workflow is as per the business process, which includes executing a series of steps to see if information/data workflow is proper.

An example of Workflow testing is verifying the transition from signing up and then logging into the application with a valid ID. This process validates the flow between two pages and functionalities using the right data. Even negative data sets test if the workflow rejects the wrong information in such a case.

Security Testing

This type of testing is to understand the security lapses in software to identify possible vulnerabilities that hackers can exploit. It is critical to check the safety of the data/information flow from one system to another. For instance, a loophole on the signup page can compromise the confidential data of every user of the application.

Here, testing of the interface is done through processes such as Penetration testing and access-control testing. An example would be to check only a user that has access is able to login. Any other attempts with invalid data should not be allowed. Here, testers also try to test the robustness of the system against possible hacking attempts.

Functional Testing

This testing approach undertakes to verify all the functional aspects of an application. In simple words, functional testing takes care of every small part of the application which has a certain function. Like ‘Forgot Password,’ drop-down menus, images/vidoes, signup/sign-in, search, and much more come under functional testing. It checks for error-free data transfer between different modules. Most often than not, functional testing comes under the black box testing technique, as testers do not access the source code.

An example of functional testing is checking for a return order window and seeing if it works for users as intended for an e-commerce app. Other examples would include verifying the drop-down menus, website clicks, right link placements, and search showing the right results.

Load Testing

This testing type validates how much load/traffic an application can withstand before it crashes down due to heavy influx. The idea is to determine the threshold of the software as in, how many users maximum, can access it at one time, without it breaking.

One example of load testing is checking the application’s ability to handle heavy traffic by hitting the server multiple times.


Often, code defects are the reason behind any runtime error. Various tools such as debuggers and profilers are useful to detect runtime errors.

An example of runtime error detection is looking for any possible issues while logging into an application. Another example would be to check if there are any broken elements or click issues on the screen after you open an app on your phone.

Best Practices

You can perform Interface testing in two ways: Bottom-up and Top-down approach. For a better understanding of what these options are and how they function, you can read our blog.

But despite your choice of one of these two approaches, there are a few best practices that you must follow as a tester to ensure that the application interface is working as per expectations.

Understand and Define Your Requirements

Before you start any project, it is advisable to accurately understand the requirements and document them to avoid missing out on critical points. Similarly, before conducting Interface testing, testers should lay out the testing requirements to build test cases on the same – positive and negative.

Write Relevant Test Cases

Running test cases manually is a laborious task. It is time-consuming and asks for more than just a keen eye. It requires patience, the right knowledge about the application, and sufficient resources to manually perform all the testing activities. That is why creating test cases that are relevant to your software will ensure that you don’t waste time executing something that does not apply to you.

Build a Test Data Set

Before you design and execute the test cases, create a set of test data that will fuel your testing efforts. And make sure to add all the information for the data to mimic real-life scenarios, so you can check if your application is user-ready or not.

Check on Different Platforms

Different devices have differing resolutions, user-friendliness, and size; it only makes sense to run Interface testing on multiple platforms to validate the overall intuitiveness of your software for easy usage.

Document Clearly

Do not skip or forget the documentation part. Record every test run and result so you can use it later to troubleshoot any bugs.

Use a Testing Framework for the Automation of Interface Testing

Running Interface testing on several devices with different test data sets can be time-consuming. The process can become redundant, and as more features get added, the test execution will require more resources too. With the use of a test framework, testers can automate these interface tests. Automating these tests helps save time and effort that can be used in other testing activities.

Here is a guide with in-depth discussions on dos and don’ts of automated testing.

Check out the guide

Tools for Automating Interface Testing

Here are three of the most popular and easy-to-use test automation tools for interface tests:


The AI-powered, no-code, open-source test automation platform, Testsigma, is the perfect tool for running your easy and complex test cases whenever and wherever. Deploy it locally or on your cloud, use plain English to write your test cases, debug and view test reports easily, and empower your test scripts to automatically fix using Testsigma’s AI. Testsigma lets you automate your tests for UI (web, mobile and Desktop) as well as APIs.

Start automating your interface tests for GUI and API, in minutes, with Testsigma


Although Postman is an API testing tool, it still is accessible to run functionality, performance, security, and integrity testing using API requests. All of these are the type of testing that comes under the interface of an application.

Using API calls, you can check the performance of the software based on its time to receive data from the server. For security, testers can use HTTPS through API requests. Even functional and integrity testing are possible. You can check the former by verifying server uptime, page tags and structure, and page headers. Integrity testing checks if the flow of data to and from your page is from verified sources. You can do it by verifying the validity of your webpage links. You can read more about it here.


Another API testing tool that supports entire functional testing as well as SoapUI. It supports Data-driven testing where you can pass the data in CSV or Excel format. As per your requirement, you can easily execute security and load testing as well, similar to what we mentioned for Postman. Overall, Interface testing is possible with SoapUI as it contains almost all types of website interfaces to run the test cases.

You can explore many other UI testing tools that will automate your Interface testing journey to ensure your application is user-friendly and easy to use.


No application is ready for users and market release if the interface check is still pending. Before customers understand the background of your software, they look at its interface and learn the functionality. And if the basics are not working properly, your application is doomed to a failed announcement.

But the solution comes in the form of Interface testing that consists of many different testing types to ensure that your complete application is working as per expectations. We list down why you must go for testing the interface (in the form of advantages) and tools that you can use for your business/project. And if you want a few examples, they are also present for you to understand the concept better.

Frequently Asked Questions (FAQs)

What is User Interface testing, with example?

User Interface testing or UI testing is checking the front-end aspects of any application that users interact with. Examples of UI testing include functionality, visuals, and performance of the UI of the product. The general test cases would include verifying UI element size, font, input fields, screen resolution, text alignment, image quality, broken elements, and more visible on the screen.

What is the difference between interface testing and integration testing?

Interface testing pertains to checking the communication between two sub-systems or components. For instance, UI is the interface between users and the application. And API is the interface between the backend and the application. Integration testing checks how two or more modules of the application integrate and transfer data among themselves.

What is an interface in API testing?

API is an application programming interface; it is an interface for communication between the application and the backend.

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