Load Testing For Beginners

Load testing identifies whether the infrastructure used for hosting the application is sufficient or not. It is used to find if the application’s performance is sustainable when it is at the peak of its user load. It tells how many users the application can handle and the scale of the application required in terms of hardware, network capacity, etc. to access the application. It helps you identify the maximum operating capacity and any bottlenecks and determine which element is causing degradation.

It is done under controlled lab conditions to compare different systems’ capabilities or accurately measure a single system’s capabilities. It involves simulating the user’s load for the target application. It helps you to determine how your application behaves when multiple users hit it simultaneously. The main aim is to define the amount of work a system can handle without performance degradation.

Examples of load testing include:

  • Subjecting the server to a large amount of traffic.
  • Assigning jobs to the printer in a queue.
  • Running multiple applications on a computer.
  • Reading and writing data to and from a database continuously.
  • Downloading a lot of files from the internet.

Steps to initiate Load Testing

  1. Test environment setup

The environment for the load test is set up. The domain should be set up close to the production environment as possible in terms of hardware, network, software specifications, etc

  1. Define performance criteria

The performance metrics for the load test are defined here, and the success criteria are finalized. it includes defining acceptable limits on throughput, response time, transactions, etc

  1. Planning the test

It involves the development of a clearly defined load test plan and set up the test environment.

  1. Creation of virtual users (user)

Involves the creation of Vuser scripts that contain various tasks performed by the end user. Each action conducted by users could be measured as transactions.

  1. Creation of scenarios

A combination of machines, scripts, and users that run during a testing session. Scenarios are of two types: manual and goal-oriented.

  1. Running the scenario

The load is emulated by running multiple tasks simultaneously. Before running the scenarios, scenario configuration and scheduling must be set up. You can run the entire system, user groups, or individual users.

  1. Monitoring the scenario

The scenario could be monitored using the Loadrunner online monitors such as run-time transaction, system resources, Web resources, network delay, etc.

  1. Analyzing test results

This is the last step in the load testing process. In this step, the tester analyzes the performance bottlenecks using graphs and reports generated during scenario execution. The load test may have to be repeated after fixing issues identified in the load test to ensure that the identified performance bottlenecks are fixed.

Need for Load Testing

Extreme downtimes have been experienced by some highly popular pages as they get large amounts of traffic. In order to ensure optimum device efficiency, e-commerce websites spend heavily in promotional promotions, but not in load checking, as the marketing brings in traffic. 

When they experience heavy traffic, several pages suffer delayed load times. Just a few facts – 

  • After 8 seconds of delay in loading a tab, most users click off. 
  • $4.4 trillion lost per year because of bad results.
  • Load testing gives confidence in the machine & its performance and reliability. 
  • Under high consumer tension conditions, Load testing helps detect the bottlenecks in the device before they emerge in a manufacturing environment. 
  • Load testing offers exceptional protection against bad results and accommodates compatible performance improvement techniques and manufacturing environment control.

Goals of Load Testing

  • Response time for each transaction.
  • Performance of System components under various loads.
  • Performance of Database components under different loads.
  • Server configuration issues like a Web server, application server, database server etc.
  • Hardware limitation issues like CPU maximization, memory limitations, network bottleneck, etc.


  • Issues that are related to performance and bottlenecks can be identified before production
  • Scalability is improved in terms of database, applications, network, etc
  • There is minimal risk associated with the downtime of the application. 
  • The cost of failure is reduced, and customer satisfaction is increased.


  • You need programming knowledge to use load testing tools.
  • Tools are expensive, as pricing depends on the number of virtual users supported.
  • Replicating a production environment

Load Testing Metrics

  • Memory Utilization: The amount of memory used while processing the request.
  • Wait Time: The time it takes from when a request is sent until the first byte is received.
  • Transactions passed/failed: It merely shows the total number of transactions passed.
  • Throughput: It is measured in bytes, and it represents the amount of data that the users receive from a server at any given second. 
  • Response time: It is the most critical parameter that reflects the quality of a Web Service. Response time is the total time taken after the client sends a request. It includes the time the message remains in transit, which cannot be measured by any load-testing tool. The result will be a graph that measures the average response time against the number of users.
  • CPU Utilization: The amount of CPU time used while processing the request.
  • Load Size: The number of virtual users trying to access the Web Service at any particular interval of time.

Types of Load Testing

  1. Load Testing

As expected, this is the bread and butter of every load tester, where you test how a system behaves with many users and the response time received for pages under different scenarios.

  1. Stress Testing

Stress tests tell how many users can your application handle.

In this, you will write the test that includes more users than your application typically has, and how much it will handle.

A stress test has only a couple of steps, or it can be many. No matter how many actions you include, this type of test is about finding out what happens when pushing your app’s performance limits — so don’t worry about being too aggressive.

  1. Spike Testing

The spike test is defined by the short time at an average level, then a quick ramp-up time to the “spiked” level. 

  1. Soak Testing

If you expect a long average session duration from users or you want to imitate a lot of traffic in only a few hours, then the soak test should be in your performance testing life cycle. The soak test lowers down performance issues stemming from a system being under pressure for an extended time. You can find out about the long-term problems conducting soak tests, like resource leaks, memory leaks, the degradation that occurs over time.

Best Load Testing companies


A1QA is a software testing company that was founded in 2002. It is located in Denver, where they have 200+ employees with specialisation in application testing and cybersecurity. 

They first serve mid-market clients in the IT industries. It helped an economic research institute in the development of a bespoke economic case management app.

load testing

Former Clients

  • Pearson
  • SAP
  • Adidas
  • Acronis


QATestLab is a software testing company with its headquarters in Kyiv, Ukraine, and an additional office in New Jersey. It was founded in 2005, a team of 67 specializes in various types of testing. They work with small mid-market clients in the IT industry. It offers usability testing for a mobile accessories provider.

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Core Services

  • Manual Testing
  • Test Automation
  • Managed Testing
  • Load testing
  • Test Documentation
  • Consulting
  • Quality Assurance


QA Mentor is a software testing company, and it is located in New York. It has 175 employees, and it was founded in 2010. Application testing services is their specialisation.

QA Mentor offers testing to identify bugs in a planning platform’s software. With the help of a matrix, the team tested the platform and provided daily updates. The client enjoyed working with them.

Former Clients

  • Cie
  • HSBC
  • Citi
  • Morgan Stanley
  • GameCloud


QualityLogic is a software testing company, and it is located in Boise, Idaho, with its offices in California and Oklahoma. They have a team of more than 68 people who specialise in application testing. They work with enterprises and mid-market clients in the entertainment, art, and music industries.

QualityLogic offers software testing services for a communication application. They conducted manual and exploratory testing for mobile and web apps.

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Former Clients

  • HP
  • Cisco
  • Adobe

Best Tools for Load Testing

Apache JMeter

JMeter is an automation testing tool that performs load tests, functional tests, regression tests, and different technologies. It supports various types of applications, protocols, and servers like  SOAP, TCP, FTP. SOAP, LDAP MOM, shell scripts, Mail Protocols, Java objects, database.

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  • It is open-source software.
  • Interactive and straightforward GUI.
  • It is highly stretchable.
  • The tests are stored in XML format.
  • It is platform-independent.
  • Best API automation tool.


It is free to use.


NeoLoad is an automated testing platform for organizations continuously testing applications. The platform offers testers and developers automatic test design and maintenance, fast root cause analysis, built-in integrations with the entire SDLC toolchain. It lets you reuse test assets and results from functional testing tools. It supports the full range of web, mobile, and packaged applications, such as SAP, to continuously schedule, manage, and share test resources and results across the organization to ensure application performance



  • Automated API Tests
  • Dynamic Infrastructure
  • Resource Reservation


You need to visit the website for the price.


The eggplant testing tool is an automated application testing and debugging tool. It tests a single source of truth for the user experience. Eggplant’s solutions can try cases at any layer from the database.

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  • It is the best GUI automation testing tool.
  • The testing is done from the user perspective.
  • It is reliable, and the tests are done quickly.
  • It uses a single test script for various scenarios.
  • Integrate with popular test management tools.


The license costs around $3400—the second stream costs around $1,700, and the third stream around  $850. 

Telerik Test Studio 

Telerik Test Studio is a testing tool. It is well suited for load, API, and performance testing. It allows you to test mobile and desktop web applications. 

Test studios combine code-based and code automation capabilities. It has a user-friendly interface that makes automation testing fast and highly maintainable.

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  • Scriptless test recording and playback.
  • Element abstraction and reuse.
  • Sentence-based UI validation.
  • Support for HTML, AJAX, WPF, and ASP.NET MVC application testing.
  • Best automation testing tools for .net.


Test Studio Web & Desktop for $2,499, Test Studio Runtime for $349 and Test Studio Ultimate is for $3,499.

Frequently Asked Questions

What is the basic flow of load testing?

The flow of load testing is:
1. Planning the test: – Plan what type of testing needs to be done. 
2. Creating Virtual Users:– The main goal of load testing is to verify the expected usage of an application. Hence virtual users need to be created.
3. Creating the scenario:- You have to create test scenarios to determine the load the needs to be given to the system.
4. Running the test against the plans created.
5. Analyze the tests to see if the results of performance are as expected.

Describe how to identify memory leakage using LoadRunner

A processor is running in the system of an application. Initially, it identifies the processor and performs a facility to check the designated processor’s memory consumption. When the test executes, it is needed to track the memory of a specific processor running in the system. The processor memory is increased when the trial is stopped. At this point, the memory leak can be concluded.

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