As a software tester, you will have heard of “black box testing” and “white box testing,” but what are they, and what is the difference between black box and white box testing? We’ve previously written about functional testing and smoke testing as part of our Types of Testing blog posts. In this post, we’re going to talk about the differences between black and white box testing. Both types of testing are vital in producing quality software, but the difference is the approach to these testing methods is considerable.

Black and white box

Here’s the short answer to this question:

Black box testing validates the requirements and specifications, whereas white box testing validates the code.

Let’s take a closer look at both.

What is Black Box Testing?

Black box testing is a method of testing software in which the internal workings (code, architecture, design, etc.) are not known to the tester. Black box testing focuses on the behavior of the software and involves testing from an external or end-user perspective. With black box testing, the tester examines the software’s functionality without looking at the code or having any knowledge of the application’s internal flows. Inputs and outputs are tested by being compared to the expected output. If the output doesn’t match the expected output, a bug has been found.

The term “black box” is used because you don’t look inside the application. For this reason, non-technical people often conduct black box testing. Types of black box testing include functional testing, system testing, usability testing, and regression testing.

What is White Box Testing?

White box testing is a method of testing software in which the internal workings (code, architecture, design, etc.) are known to the tester. Therefore, it validates the internal structure and often focuses on improving security and making the flow of inputs/outputs more efficient and optimized. In this kind of testing, the tester looks for internal security holes and broken or poorly structured coding paths.

The term “white box” refers to having visibility into the internal workings. Because of this, a more technically skilled person conducts the tests. Different types of this process include unit testing and integration testing.


Black box and white box testing have the same goal; to improve and maintain quality in the application. However, because of their different approaches, they require both technical and non-technical individuals. When you combine both testing methods, your test coverage will be wider, and you’ll find an increase in overall quality.