Recently I happened to be in an interview where I was asked to explain feature testing and functional testing. Even after looking up so many references I am unable to find a convincing explanation ‒ can anyone explain?

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    It could be also misunderstanding from interviewer or interviewee: "functional" vs "functionality". Which is also in your question: title mentions "functionality" but question body mentions functional. "functional" is often considered a synonym for "system" or "integration" testing. Sep 30, 2014 at 15:01

9 Answers 9


There are lots of kinds of testing, and they vary by company and organization. Different people use different terms. There is no special value in any particular set of terms; you just need to know what the speaker means when they use them.

Frankly, I think it was a stupid question, or perhaps even a trick question to see how you deal with ambiguity. Whether a candidate happens to know how the interviewer happens to define a set of ambiguous terms has no bearing on job performance. I hope the rest of the interview was better than that.

  • During an interview asking a stupid/trick question like this might be interesting even if the interviewer does not know the answer. A good answer can be "I don't know the exact difference, but I think it could mean ..... depending on the situation." As an interviewer I want to know how your train of thought is, not if you can explain definitions by head. Sep 30, 2014 at 14:47
  • Exactly. My response would be mention two approaches to tests: testing certain feature, and testing overall functionality. Then you may ask what terminology this company uses for each. To make names more distinctive and less misleading, it would help if name starts with different letter, not "F". But local customs vary :-) Sep 30, 2014 at 14:58
  • Maybe real goal of the question was to find out if interviewee can investigate ambiguous question, ask probing questions to determine what customer has really in mind, test not knowledge but communication skills. If so, this question would be a masterstroke :-) Sep 30, 2014 at 15:01
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    Yeah, I can't help but think this was a pointed question to try and see whether a candidate will then explain their understanding of the different types of testing which can be applied, and specifically when they would apply them. I'd have said "Well, I'm not sure how you define those here, but I've always gone by <talk about the main types of testing, how I would prepare for and implement them, define why they're important for coverage and quality>" Sep 30, 2014 at 15:51

This is where good communication skills, alertness and good vocab comes in handy for a tester....

Looking at the meanings of the terms in question,

Feature: a distinctive attribute or aspect of something.

Functionality: the quality of being suited to serve a purpose well; practicality.

So with the knowledge of the meanings of these terms you can come up with a good enough explanation spontaneously. As it is there are many terminologies made by people in testing. And to different people and organizations a term may have a different meaning. So it is always better to give an appropriate explanation depending on the context.... :)


Unlike for other Testing types, for the term Feature testing, you can find only a best match from well accepted testing types in Software QA domain.

  • Feature testing - I think it is the sanity test. In a mature build, particular feature could be newly added, or existing feature's bug could be fixed. Then the testing has to be carried out focusing the particular feature alone. The sanity test of a mature build is also the same thing. However feature test (sanity test) alone would not qualify application for sending live. The regression test has to follow right after to make sure nothing in the whole system is broken by new addition of feature or bug fix. The link here should give you more understanding on Sanity test

Functional Testing has 2 interesting meanings depending on the context of testing

  1. As a sub type of System Testing Types

    • Functional Testing - Testing to look for missing functionalities which could be useful to the end users

      This is not what the simple name suggest what it could be. It is one variation out of 7 main types of system testing. System testing is also called End to end testing. One major aspect of system testing is Functional testing where testers look for missing functionalities which could be useful to the end users. Idea is to improve the quality of application by new functionality suggestions after the test.

      Please refer this link for more info on system testing

  2. Main testing type that cover many other sub testing types

    • Functional Testing - Test how system functions conform to the functional requirements provided by the customer.

      Composed of many testing sub types involving even developers in the team to contribute. Check this link for more information on this main test type.


Feature Testing: Features are changes that add new functionality or modify existing functionality.

Functional Testing: Functional Testing is a testing technique that is used to test the functionality of the Software, should cover all the scenarios.

Click here to know more about functional testing

Edited as per the comments.

  • Downvoted because the answer is just a bunch of links.
    – user246
    Sep 30, 2014 at 15:00
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    Ok, but don't mind your answer is not showing the differences?. But I honestly accept that I just posted the links.
    – QA4it
    Sep 30, 2014 at 16:11
  • Agree sir. Thanks. If there is a then what is that difference and if there is no difference then the answer is there is not difference (Both are same).
    – Sachin
    Sep 30, 2014 at 16:20
  • Yup, I agree with you. The question heading is functionality and in description you can see functional.
    – QA4it
    Sep 30, 2014 at 16:32

Feature testing involves testing specific features or functionalities of a product to ensure that they are working as intended. This type of testing is often focused on user-facing features and involves testing things like buttons, links, forms, and other interactive elements of the product. The goal of feature testing is to ensure that each feature is functioning correctly and delivering the expected value to the user.

Functionality testing, on the other hand, involves testing the overall functionality of a product to ensure that it is meeting the requirements and specifications that have been defined for it. This type of testing is often more comprehensive and involves testing the product as a whole, rather than focusing on individual features. Functional testing may involve testing things like performance, security, compatibility, and other aspects of the product that are critical to its overall functionality.

So, in summary, feature testing is focused on testing individual features or functionalities of a product, while functionality testing is focused on testing the overall functionality of the product as a whole. Both approaches are important and can be used together to ensure the quality and reliability of a software product.

  • Source, please?
    – Joey Rock
    Mar 23, 2023 at 7:27
  • 1
    @JoeyRock yes, check this out Mar 23, 2023 at 7:29
  • Please edit your answer to put the reference in the body of the answer rather than in the comments. This is a well-thought-out answer that makes a good addition to this very old question.
    – Kate Paulk
    Mar 23, 2023 at 11:20

Feature Testing Testing enhanced things in already developed project is called feature testing.Whether its is useful for our project.Understanding the Feature,Build Test Scenarios,How it is Implemented,Deploy the Build Early are some of the things in feature testing.

Functional Tesing Functional testing means testing the application against business requirements. Functional testing is executed using the functional specifications given by the client or by the design specifications according to use cases given by the design team. Role of functional testing is to validating the behavior of an application.

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    So doesn't a new project have feature? Or only the next versions have features? Feature does not mean update! Sep 30, 2014 at 16:13

Feature is something that the user perceives as a benefit. Something that can be called out in a brochure bullet point.

Function is something that gets done.

In general, features use one or more functions. For instance, "undo" is a feature. It is a cross-cutting concern, and is actually composed of many tens or hundreds of individual "undo" functions.


A function does something; features are characteristics or qualities of the function, or perhaps how it does what it does.

When assessing software, should buyers look at functions, features, or both? I would think that the focus would be on functions (what you’re looking for the system to do for you), as these are fairly easy to identify. Features may vary from vendor to vendor, though functions may be almost universally available. And so, you might consider the features of one vendor versus another, as a way to decide which you prefer.


Function is like the basic thing of the product or of particular domain for example, on a job searching site job seeker can view job which is basic functionality of all job searching site, but in particular job searching site one can send mail to the recruiter as well is feature of the particular job searching site which belongs to a particular company.

It means functionality is the basic function of the product in a domain, but features can change depending on company to company product in the same domain.

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