Functional Testing Vs. Performance Testing: Benefits Of Using Both

Functional Testing vs. Performance Testing: The serge of products in the market and increasing competition have made quality assurance an integral part of the Software Development Life Cycle (SDLC). Introducing a product without addressing customers’ demand and removing bugs is like wasting money and effort because today’s smart customers don’t get sold easily.

That’s why it’s important to maintain quality throughout the product development cycle and give customers exactly what they want with a great user experience. Performance testing and functional testing are two important types of quality assurance that help achieve these objectives.

Unfortunately, some companies don’t understand the essence of quality assurance and software testing, so they are stuck over the question: should they hire performance testing services or functional testing services? But before decoding this question, let’s find out another important question: what is the difference between performance testing and functional testing? So, let’s find out performance testing vs. functional testing.

Performance Testing vs. Functional Testing: What is the Difference?

The main difference between performance and functional testing is the difference in their objective. The functional engineers focus on “Operability” of the product, i.e., how the product works or performs after receiving the input signal. How that product performs, the “Efficiency,” is taken care of by the performance testing.

Let’s understand these testing types a bit deeply:

Functional Testing Services

Functional testing services ensure that software responds according to the predefined specifications and gives the desired output after receiving a specific input. A functional test checks the system’s accuracy and interoperability to work accurately.

A functional engineer doesn’t approach quality from a performance engineer’s perspective. So, functional testing has nothing to do with the system’s speed, load time, and efficiency. That’s where performance engineers enter the scene of quality assurance.

Performance Testing Services

Performance testing services focus on bringing “the best” factor to software. A performance engineer works on multiple layers; for example, it checks if software:

  • Sustains the increased demands and performs the same way.
  • Endures different functioning environments without collapsing.
  • Qualifies the user’s expectations.
  • Validates the response time.
  • Checks scalability and speed in different scenarios.

So, performance testing works at scale, focusing on various factors that improve, maintain, and regulate the system’s efficiency. Some performance testing styles include spike testing, stress testing, load testing, and soak testing.

To wrap performance testing vs. functional testing in one line: Software can give the desired output, but it doesn’t define how long it will take to give this output.

It shows both these types of testing work on different scales and layers. So, it is not wise enough to consider one type as the replacement of another, and QA testing is incomplete without employing both these testing types.

So, instead of focusing on whether you should choose functional testing services or performance testing services, the approach should be on how to use both these types to gain the maximum benefits.

Performance Testing vs. Functional Testing: How to Use Both?

Functional testing is used during the development phase, and performance testing helps ensure better software quality after functional testing.

Use of Functional Testing

The best functional testing approach implements functional tests throughout the development phase instead of after product development. It helps catch any glitch or bug at the beginning of the phase, saving money and effort. For example, test-driven development (TDD) methodology focuses on creating functional tests before the development phase to execute tests along with every development phase to stay safe.

Use of Performance Testing

You can’t check the performance of anything if it doesn’t exist. So, performance testing takes place after the development phase. Don’t skip this test because launching a product without ensuring it fulfills customers’ demands is like welcoming the possibility of the deluge of negative feedback. It is always better to stay one step ahead to earn customer trust and market share. That’s why performance testing is not just an option but a necessity. Implement performance tests on every product feature once the functional engineer verifies it.


Tech-market is in a state of flux, with every day bringing something new for the tech geeks. However, launching a product doesn’t ensure it will also gain popularity. Your customers are aware; they have tested your competitors’ products. So, releasing something better will only capture customers’ attention – nothing less. That’s why the need is to develop an all-encompassing quality assurance and software testing approach and use both performance testing and functional testing at the right time. This multiple testing approach will go a long way!

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