Web Performance Testing: What It Is and Why You Need It

Software Quality Assurance 09-May-2023

Performance testing is one of the most challenging components of web application testing. But it is worth it: if done right, performance testing can forecast product behavior and its response to user’s actions with an impressive amount of detail and precision. Irrelevant web performance test data or wrong metrics chosen during testing cost companies a lot of money and effort, while not monitoring your web application performance at all can lead directly to a crash, say, on Black Friday, if you are not prepared to handle an increased number of concurrent users.

Business or product owners needn’t know exactly how to performance test a website, but it’s useful to have a basic understanding of procedures that you pay for. From this post, you can learn what web application performance testing is, when it should be done, and how. Then, you will be able to make an informed choice whether to hire testing specialists or run testing sessions on your own.

Types of web application performance testing

Performance testing of a web app is, simply speaking, a process of using software tools to simulate how an app runs under an expected workload and measuring according to benchmarks and standards. It focuses on a wide range of metrics and characteristics — QA professionals assess response time, resource utilization, system throughput, and so on. We designed the classification below to help project teams ensure they don’t skip a single crucial testing aspect. Here are the main types of web application performance testing:

1. Performance testing

A performance test is any test that measures stability, performance, scalability and/or throughput of your web application. It is used to ensure the final build meets the expectations of an end user and helps a business achieve its objectives. Ideally, owners should end up with a list of mismatches between expected and actual performance of their web application. Having a deeper insight into the weaker points of your app helps during fine-tuning and brings more substance to the decision-making process.

2. Load testing

Load testing evaluates the web application’s ability to perform under increased load, e.g., under a massive number of concurrent virtual users performing transactions. Load tests would look at how their actions affect the application’s response time and measure the staying power. Engineers will pinpoint and fix concurrency issues and ensure they have enough server power and bandwidth to support an estimated load. This type of testing is a must for scalability planning.

3. Stress testing

Crashes may happen to anyone, and some product owners would say they are unavoidable. But it is crucial to ensure that no data is lost during the shutdown and no security exploits are out in the open. Stress testing helps teams define issues that only become visible under peak load conditions, and it evaluates the extent to which a system keeps working under intense loads or with some of its hardware or software compromised. To run stress tests, QA specialists simulate loads that exceed reasonable estimates to test the performance of web applications. The results should be used by managers to prepare the maintenance team for extreme situations.

4. Capacity testing

A capacity test is a test to determine how many users your application can handle before either performance or stability becomes unacceptable. By knowing the number of users your application can handle “successfully”, you will have better visibility into events that might push your site beyond its limitations, whilst your system admins will know what server capacity, bandwidth, etc. are needed for high-quality, error-free product performance.

5. Component testing

Any kind of web performance testing can be handled as component testing. It’s an approach that aims at the system’s architectural components. Networks, servers, databases, storage devices, firewalls, are all examples of these discrete components.

6. Smoke testing

A smoke test is the first run through a developed application that helps determine its weakest points and most pressing issues. Smoke tests are usually performed under normal production conditions, with an estimated user load and data volume. If the test fails, no further testing is necessary until the simplest test has passed successfully. It is a best practice to initiate one of these “verification” runs before running larger tests to ensure that the test is valid.

7. Unit testing

The purpose of a unit test is to ensure that a unit of code works as expected. The typical unit of code is a function. A unit test submits data to a function and verifies the accuracy of the result of that function. Typically, unit tests are performed directly by developers. Unit testing is a way to smoothly incorporate the validation of system performance into the development cycle.

8. Investigation

To determine the root-cause of the problem, a team needs to run investigations — gather performance-related data. All the insights collected during the investigation help testers back up or disprove a hypothesis regarding a cause or a solution to a performance issue.

9. Validation

Validation tests determine if a system matches a set of business requirements and expectations. Developers usually validate the following characteristics of the project:

  • Speed
  • Stability
  • Scalability
Web Performance Testing - What It Is and Why You Need It

The objectives of web application performance testing

Performance testing is a way for companies to be proactive, detecting and neutralizing potential risks before bringing the product to the market.

Failing to validate the system properly usually results in high opportunity cost, reputation losses, low conversion, and user satisfaction rates.

Namely, project teams conduct performance testing for the following reasons:

  • Detecting system bottlenecks. This is usually the main aim of any performance tests. Bottlenecks can cause negative user experience, or even software crashes. Some common bottlenecks include slow response time, poor scalability, system downtime, etc. Testers can change user loads, data volumes, and access the WPA from a range of locations. After careful observation, they will be able to pinpoint performance issues and brainstorm cost-efficient ways to handle these problems before rolling out the product on the market.
  • Ensuring that the project is stable across different platforms. Performance testing helps ensure that end users can access a designated number of features on all supported platforms. Different devices, browsers and operating systems influence the load time and other metrics, so performance tests are a must to protect yourselves from the risk of losing potential leads due to the poor support of one or several operating systems.
  • Ensuring that there’s no product degradation since the last release. Any major code change has to be followed with performance tests of your web application. You have to be sure that the quality of the system’s performance hasn’t dropped.
  • Checking if the product complies with SLAs, contracts, and current regulations. The data that is obtained as the outcome of performance testing is essential for all project stakeholders — based on the insights, they can assess the development team and determine whether a product is ready to be brought to the market.
  • Finding the ideal configuration for an app in terms of throughput, components utilization, and response time. Performance testing helps predict how many system resources are needed to maintain web applications. After the testing stage is complete, the project team will be able to create a configuration that delivers high-quality performance without compromising business objectives.
  • Reducing downtime-induced revenue losses. By being able to pinpoint the warning signs of possible system shutdown and fine-tune the web application, a product owner can reduce the risks of downtime, as well as reputation and financial losses it brings.
  • Improving the quality of scalability strategies. To determine what budget, team, and effort the scalability process will require, you should be aware of the system capacity and resource usage. Performance testing promotes responsible scaling and helps managers synchronize the activities of marketing and development teams.

Step-by-step guide on how to do web app performance testing

Web app performance testing is so diverse and dependent on a set of objectives set by each business manager that developing a single, unified guide that fits web-application testing across all domains is nearly impossible. We’ll take a look at the fundamentals that all successful performance tests share. Here’s the list of critical tasks to provide developers, testers, and business managers with the full view of the system.

1. Set up the test environment

First of all, you need to figure out what sorts of conditions your application will actually face in production. Your secure, fully functional testing environment has to simulate production as precisely as possible. Usually, testing environments include:

  • network configurations;
  • hardware;
  • software tools.

Taking time to establish a functional test environment improves the quality of planning and running tests. Also, keep in mind that creation of the performance testing environment should involve both developers and testing engineers.

2. Identify performance criteria

First-tier performance criteria that are assessed for all web apps are usually the response time, throughput, and resource utilization. Depending on your business requirements, additional metrics might be measured and captured.

3. Plan tests

Thorough research is a cornerstone of an intelligent testing plan. The testers identify key scenarios to test for all use cases and some specific situations the application is likely to encounter. To understand why performance suffers at a given level of users, they need to know what those users were doing, and for that they might (or, most often, will) need your staff’s help. After testers have collected a range of cases, they need to come up with ways to simulate needed interactions. They also will define metrics that will be captured during the testing.

4. Configure the environment

At this stage, a QA team creates a toolkit of load-generation and performance-monitoring tools. The testers create a bank of IP addresses to use during sessions. As project testing moves along, it’s a common practice to modify or expand the web server performance testing toolkit to provide a broader view of the web application’s performance.

5. Execute tests

The success of test execution depends on the way your team has handled all the previous steps. Other than that, here are the practices to follow as you execute performance tests:

  • assign a person responsible for monitoring;
  • have a habit of regularly validating test data, systems, and scripts involved;
  • review all test results to ensure there were no flaws in the process;
  • keep logs of all tests in case you need to re-iterate them later during the application life cycle;
  • execute smoke tests before moving to the real ones;
  • as a rule of thumb, QA professionals usually execute each test three times.

6. Analyze and compose results

Once the web app’s performance has been tested, the team will analyze the test results using graphs and reports generated during scenario execution. Now their findings are shareable, and they can offer their solutions to any issues identified. They fine-tune the app, and after fixing the problems, rerun the tests using the same and different parameters to measure improvement.

Note that as a stakeholder, you don’t have to be satisfied with a full technical report. What you need is an explanation of how the testing outcome translates into business needs.

7. Reiterate

In fact, the results of performance testing are never set in stone. Successful performance testing consists of repeated and smaller tests. As soon as the code changes, there’s a likelihood response time and other metrics will be affected. That’s why re-iteration is a core part of a successful performance testing strategy. Create a detailed schedule with the re-runs to not forget about re-validating the system. Successful performance testing consists of repeated and smaller tests.

Web Performance Testing - What It Is and Why You Need It

Performance testing tools for web applications

As there’s a variety of testing activities, performance testing specialists need a broad toolkit for web application performance testing. From a wide range of existing and suitable tools, for this post we’ve selected five of our favorites.

1. PFLB Platform

PFLB Platform is a new generation platform for load and performance testing that enables dev and QA teams to run scalable and continuous testing for websites, mobile, api and software.PFLB Platform is definitely your choice, if you want to run the tests yourself: the tool creates tests automatically based on your Google Analytics visits/pageviews data (which does not mean that you can’t run your own tests – of course you can).

Just choose your goal and the number of users or run a test with recommended parameters. You will be able to track performance as soon as you start the test. No coding skills needed!

2. JMeter

JMeter is among the most powerful load and stress performance testing tools for web applications. It helps testers simulate heavy traffic loads and test the strength of a network or a server. JMeter has a wide range of supported protocols — Web, FTP, LDAP, TCP, Database (JDBC), and many more. There’s a fully functional IDE to give testers as much control over executing and monitoring load tests as possible.

3. Gatling

Gatling is a framework that covers load and performance testing. It is an open-source tool with a straightforward interface and a range of features that are fully geared towards web applications.

The range of protocols supported by Gatling includes HTTP, Server-sent events, WebSockets, JMS, AMQP, MQTT, and ZeroMQ. Along with HTML-rich reporting and a built-in DSL, Gatling provides testers with a wide range of plugins — testers can extend the tool’s functionality in a way that benefits the testing framework.

4. BlazeMeter

BlazeMeter is a load testing platform that spans websites, web applications, and software. A tool is equipped with a range of plugins — there’s a Jenkins CI module, a dedicated Drupal module, and an integration with JMeter.

BlazeMeter is one of the most functional load testing tools that took the entire process to the cloud.

5. Loadrunner

Loadrunner is an application testing tool that helps analyze system behavior and adds to the efficiency of load testing. It allows QA professionals to run automated tests as they can store all simulated interactions as scripts and use them for future testing.

Loadrunner-simulated activities include keypresses or mouse clicks. The tool supports application, database, network, and server testing. Internetworking, email protocols, as well as remote client technologies, are supported.

Web Performance Testing - What It Is and Why You Need It


Performance testing offers business managers a pool of insights, provides data for efficient decision-making and minimizes the number of risks the team may encounter after the product release. Skipping crucial steps or stages of the process, on the other hand, can mislead stakeholders and greatly overestimate the performance of the product.

For a performance testing service, be sure to hire a skilled and experienced team. PFLB has 400+ certified testers on board that have handled over 300 projects with multi-layered infrastructures across challenging domains — finance and banking, healthcare, etc. You can find our company in the Software Testing Companies list on the website DesignRush. To get a skilled team of testers to work on your project, contact us!

Source: PFLB