Most common types of software bugs in QA Testing

As per Wikipedia, "A software bug is an error, flaw or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways".

Comprehensive testing and optimizations are needed because errors need to be identified, recorded, and resolved. If testers are aware of the most common types of bugs or defects they are likely to encounter, they can tackle them earlier, faster and more effectively. So next we will discuss the most common types of software bugs or defects encountered in software testing.

Functional Bugs

A functional bug means that the program does not work as intended, each type of software has its unique quality requirements, any component in an app or website that doesn’t function as intended is a functional bug. Such bugs are often detected when testers conduct comprehensive functional testing for their apps or websites in real user conditions. Functional bugs can be fixed by performing functional testing.

Integration Errors

Integration level bugs are defects that occur when two or more units of code written by different developers fail to interact with each other. These defects can be difficult to find and fix. It requires coordination between multiple teams. However, they can have a significant impact on the overall quality of the software. Integration bugs can be fixed by performing integration testing.

Performance Defects

Performance defects are related to speed, stability, response time, and resource consumption by software. The bugs will impact the performance of the software. Performance bugs are caused by a number of different factors. Usability bugs can be fixed by performing performance testing.

Syntactic Errors

Syntactic mistakes are wrongly spelled terms or grammatically wrong phrases, they are the most basic type of defect. The errors occure when the code violates the rules of the programming language. Syntactic mistakes will usually prevent the code from running at all, so they're easy to spot and fix.

Calculation Errors

It is one of the most common software errors. It may happen due to any of the following reasons: incorrect logic, incorrect formulae, data type mismatch, programming errors, incorrect arithmetic operator order, etc. For example, when a wrong formula is used for calculation, incorrect logic may happen.


Defects are an inevitable in the software industry. Prevention is better than cure. You could think ahead, anticipate bugs that can appear in your mobile/web app after you fix an existing bug, the expenses of detecting and fixing bugs increase significantly as software testing progresses. Therefore, early detection of software errors is essential.

For any inquiries, please contact:

Latest Posts
1Introducing Go Language for System Transformation: Tips and Techniques for Improved Performance Because the go language natively supports coroutines and can meet both development efficiency and program performance, it was decided to introduce the go language for transformation.
2Choosing the Right API Testing Tools: A Comprehensive Guide API testing can be performed by simply recording script through tools with GUI such as soapUI, or by writing code by open source project tools
3Exploring Valuable Test Cases in the Android Official MVP Project: A Comprehensive Guide to Unit Tes This article serves as an appendix to "Interpreting the Unit Testing of the Android Official MVP Project". This MVP project and its unit testing cases can provide many insights for our work, so it is worth giving it a quick read.
4A Comprehensive Guide to XSS Attacks and Defenses This article provides a detailed introduction to XSS(Cross Site Scripting) vulnerability attacks and defenses, including vulnerability basics, XSS fundamentals, encoding basics, XSS Payload, and XSS attack defense.
5How to Make Your Go Program Run Faster? This article is about the Go language. It primarily focuses on runtime speed, rather than development speed – these two types of speed are distinct.