A Comprehensive Guide to Interface Testing [with Examples]

interface testing

Like any other testing, interface testing helps in thoroughly testing the software. It ensures that the end-user of the software does not face any heated issues.

No doubt it is tricky, but there is a requirement of proper planning to perform. One of the best ways to perform interface testing is to automate test cases, which produces robust and high-quality results. 

What is Interface Testing?

Interface testing is a type of software testing method which acts as an interacting or communicating medium between two remote software systems.’

Usually, an interface is a medium that helps two components to communicate with each other. It can be in any form like API, web design, graphics, etc.

It represents specific commands, messages, or other unique attributes. These act as a bridge between a device and its user. Thus, helping to communicate extensively. Therefore, when one tests these communication media for proper working, it is termed interface testing. 

How to do Interface Testing?

Interface testing is mainly for two primary segments. These two segments need constant care to avoid a complete breakdown of essential services. The two segments are:

  1. It is the common interface between the web server and the application server.
  2. It is the common interface between the application server and the database server.

The scenarios mentioned above are crucial for a device to work correctly. It also helps to analyze for the user to communicate actively with the system. Hence interface testing is essential for the following reasons:

● To check and verify whether the commands provided to servers are executed in proper sequence or not.

● To check whether all the possibilities of errors can be correctly handled. The appropriate error message is returned to denote the issue.

● While some operation is ongoing, it has to thoroughly check and analyze how the outcomes are provided when general connections for a web server are reset while codes are executed.

Some Examples of Interface Testing:

Consider some random application in a general XML file for the input, and the output is transformed into a general JSON file. Running an interface test on this sample output is quite easy. The tester only needs the specifications carried by the XML file format and the JSON file format.

Eventually, when you have completed all the required specifications are completed, the tester can create a sample environment.

Here the input fed in is an XML file format. When the XML file format input is provided, and the output is received in a JSON file format, the tester can match the results with the required specifications.

If the match turns out to be a positive one, the interface testing process is completed successfully.

Why Do Interface Testing?

Running regular interface tests is crucial for the health of an interface application.

It also needs to ensure that it performs correctly while communicating between the user and the device. Here is why interface testing is important for any interface application:

  • It ensures that an end-user does not face or encounter any major, minor or hindrance while using a particular software or application.
  • Helps to accurately identify the central area of use or the part of the software; constantly accessed by the end-user. It also checks the user-friendliness of that part thoroughly.
  • Interface testing checks all the working of the security requirements. At the same time, every piece of data or information propagates through the lines to complete the channels of communication between two working systems.
  • Carried on to check whether a particular solution can deal with failures in a network that connects an application server to a specific website.
  • Helps catch integration errors early in the development cycle. Since interfaces connect different parts of an overall system, testing them thoroughly reveals issues with incompatible data formats, protocols, timeouts, resource contention, and other integration problems. Catching these errors early prevents cascading failures down the line.
  • Tests end-to-end functionality and data flows across interface connections. This builds confidence that the integrated system will work as expected when deployed.
  • Shifts testing left to earlier stages of development. Interface testing can begin as soon as first components are available. This provides feedback to developers early and prevents defects from piling up.
  • Reduces project risk and the likelihood of catastrophic failures after launch. Comprehensive interface testing across all connections between components mitigates the risk of uncaught defects that could cause system-wide outages.

4 Most Common Types of Interface Testing:

The various types of interface testing methods are:

● Workflow- This method ensures that the designated interface engine deals with all the standard workflow cases efficiently and adequately.

● Edge cases and unexpected values- You can test a particular test case for a date, month, and day in a reversed format.

Performance, load, and network testing: There are two types of interface depending upon the performance: high-volume interface and low-volume interface.

You can decide this differentiation based on the engine used by the interface and the network connectivity infrastructure. Therefore, it is quite natural that any high-volume interface will need a higher load testing measure.

Individual systems: It is a common method where you can test each system or unit of a whole application individually.

For example, in retail store software, the inventory system, administrative system, and management system should work differently and efficiently on an individual level.

Read also: Scriptless Test Automation: The Complete Beginner Guide

Advantages of Interface Testing:

Following are the primary advantages:

  • It helps in verifying the communication between at least two or more components in detail. The application’s verification is one of the essential tasks for the ideal functionality of the application. 
  • Interface testing helps check the applications of the security policies for robust communication between the different components in the application. 
  • The testing helps in understanding the behavior of the application in case of server or network issues.
  • It finds out the application areas primarily used by the users. Therefore, testing them properly. 
  • The testing helps in the prevention of issues way in advance before usage by the final users. 


Thus, conducting interface testing regularly checks and verifies the functioning of a particular interface application and software.

These checks would prevent any breakdown or failure while the system is at work. It would also ensure that the end-user does not face any problems or difficulties when the system is at work.