Soak Testing – What it is & How to Do It with Example?

November 10, 2023Shanika Wickramasinghe
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Nowadays due to the extremely high market competition for software products, most software development companies focus on implementing bug-free applications with higher quality. They are always concerned about achieving functional requirements. However, if they miss the non-functional aspects, especially during software testing, that might be a key reason for decreasing the quality of the product. This is where the term “Soak Testing” comes into the arena. In this article, we are going to discuss what Soak Testing is, why we should perform Soak Testing, how to conduct such a test, and the benefits and challenges of soak testing.

Table Of Contents

What is Soak Testing?

Soak testing is a non-functional testing method that is used to evaluate the performance of a software application under a huge load for a long period.

Objectives and Scope of the Soak Test

  • Determine the stability of the system by evaluating the ability to work under a huge load without crashing or unexpected errors.
  • Detect and address potential non-functional problems such as memory leaks, resource leaks, degradation, etc.
  • Skip unexpected performance and system errors.
  • Monitor and analyze resource utilization.

The scope of soak testing includes testing the software application under strict usage conditions while evaluating its endurance and responsiveness. The end goal of it is to find any performance issues or bottlenecks that may occur during real-world use. These tests stimulate real-world scenarios to make sure that the system’s reliability is under huge stress. After identifying and addressing such bottlenecks it helps to improve the product’s overall performance.

Why Should You Perform a Soak Test?

Performing a soak test is very important to make sure that the software application is stable and reliable. It helps to detect hidden major issues like memory leaks and performance degradation. By simulating huge loads over a long period, soak testing leads to detecting and addressing those problems while increasing the system’s performance. It also minimizes the risk of system failures and ensures a positive user experience under extremely high real-world loads.

When to do Soak Testing?

Performance issues should be tested during multiple phases. Therefore, soak testing is essential at various stages of a software development lifecycle.

1. New software releases

Soak testing is important when launching new software releases. After numerous functional and performance tests, it helps to verify the stability of the software under huge and extended usage, ensuring that it performs well over time. This is critical for software updates such as security updates, the addition of features, bug fixes, and changes, as it verifies that those modifications do not introduce any hidden performance problems.

2. System upgrades

The hardware changes and software updates should be followed by soak testing. It verifies that the upgraded system can take the continuous operational load and helps identify performance issues introduced by the new updates. And it ensures that the system upgrades do not break the system’s stability.

3. Peak usage periods

Soak testing is important during peak usage periods, such as tax seasons and major events since the systems may experience increased traffic during that time. Running soak tests can help to predict how the application will perform under high loads and identify any bottlenecks. This allows development teams to optimize the systems to ensure that they can handle huge loads without any issues while providing a good user experience during peak usage periods.

When you don’t need soak tests?

Even though soak testing is very important during many phases of software development, it does not mean that it is always necessary to perform soak tests. Let us discuss some scenarios where it’s not required to perform soak tests.

1. Short-lived applications

Conducting soak tests may be unnecessary for software applications with very short life cycles or those designed for one-time use. These may not benefit from the long tests with huge loads that soak tests offer since they are not intended for continuous usage.

2. Limited resource applications

Software applications with limited resources such as simple utilities and tools will not benefit from soak testing. Those applications have fewer components and a lower risk of resource leaks or performance issues under huge loads due to their simplicity.

3. Time and budget constraints

Sometimes, the development teams have to skip soak tests due to tight deadlines and cost limitations. Soak tests can be time-consuming and resource-intensive making them not practical when project timelines or budgets are limited. In such situations, development teams have to focus on less time-consuming testing methods.

4. Stable applications

Stable applications that have undergone numerous tests and have a history of stable performance may not require frequent soak tests. If a system has good reliability and no planned significant updates, continuous soak testing might be a waste of time and money.

Who is involved in soak testing?

Software testers and performance testing experts play a key role in planning, executing, and monitoring the soak tests. They design test scenarios and oversee the test execution, Developers may also get involved in soak testing to address any issues identified during the testing process, making necessary improvements in the code and configurations. Sometimes they are involved in setting up and facilitating test environments as well. Other than that, several stakeholders such as project managers, and business analysts may also overlook the test results while understanding the objectives of soak testing.

Characteristics of Soak Testing

Unlikely the other types of performance testing methods, soak testing has some key characteristics that make it unique from the other types of load tests.

  • Long-lasting test durations (hours or days)
  • Simulation of huge loads (can be thousands or millions of users)
  • Real-world usage conditions
  • Resource utilization (CPU, memory, disk)

Benefits of doing Soak Testing

Running a soak test may result in a lot of benefits for the testers, developers, and the whole software project development team. Let’s get to know some of them.

  • Helps to make sure that the application lasts long in a stable manner.
  • Uncover memory leaks and resource allocation issues.
  • Detecting and fixing performance bottlenecks.
  • Helps to scale resources and infrastructure according to the increased loads.
  • Increases the reliability of the application.
  • Saves additional costs by preventing expensive emergency fixes and system downtime.
  • Increases customer satisfaction.

Examples of Soak Testing

Let’s take a document management web application preparing for the tax season. The testing team simulates a scenario where a high number of users continuously log in, view customer details, upload and download tax documents, and log out from the application over several hours or days. This test monitors the application’s response time, resource utilization, and overall stability under a huge load. It helps identify and address potential issues such as memory leaks, and server overloads that may impact the application’s performance during the tax season.

What do we test in soak testing?

Soak testing verifies whether any issues are occurring in the system against huge, long-lasting loads. Also, the identification of underperformance issues can be done through a soak test, testing several key aspects.

1. Stability

Soak testing evaluates the system’s ability to maintain a stable performance over a long period. It tries to identify any unexpected crashes or issues that might occur when the system is under continuous usage and sustained loads.

2. Memory leaks

Detecting memory leaks is a key objective of soak testing. It verifies whether the system properly manages memory and resources and prevents memory leaks that can fail performance over time.

3. Resource utilization

Soak tests monitor system resource utilization. Eg:-  CPU, memory, and disk space. It helps to identify inefficient resource management while ensuring that the system allocates and releases resources effectively under huge stress.

4. Performance degradation

Soak tests detect any performance drawbacks or issues that may occur as a result of a huge load. This degradation might occur due to inefficiencies in the system and the goal is to detect and correct these issues to maintain consistent performance.

5. System recovery

Under soak testing, testers evaluate its ability to recover from failures or unexpected errors during the load test. It ensures that the system can handle and bounce back from disruptions without any data loss or service downtime.

6. Data accumulation

Over time, data accumulation can affect system performance. Soak testing examines the impact of accumulating data or logs on the system’s functionality, identifying potential bottlenecks, and optimizing data management processes.

How to Do a Soak Test?

Same as most performance tests, soak testing is also a testing process that

involves several key steps. Let us dig into those steps and get to know more.

Step 1: Define objectives and scope

First, the testers have to clearly define the objectives and the scope for the soak test. They also have to determine what aspects of the systems they want to evaluate such as stability, memory management, resource utilization, etc. Then they have to determine the execution time of the test and specify the performance criteria.

Step 2: Create test scenarios

Next, need to create test scenarios that represent real-world usage. These scenarios should gradually increase the load on the application over time. There, the testers have to consider the variations in user interactions, transactions, and data volumes respectively.

Step 3: Set up a test environment

When it comes to setting up the test environments, the testers or the developers have to configure hardware, software, databases, and networking components as well. Also, they have to make sure that the monitoring tools are in the correct place to track the performance.

Step 4: Execute soak tests

When executing the test suits, testers have to increase the load on the system gradually and continuously monitor the system’s performance, resource utilization, and stability over the respective duration.

Step 5: Analyze results and report

After completing the tests, testers evaluate whether the system met the defined objectives and if any performance or other related issues were detected. They prepare a detailed report that includes test results, performance metrics, and certain recommendations from their end. Then they share it with the relevant stakeholders to take further action.

Manual and Automated Soak Tests

Soak tests can be conducted using both manual and automated approaches. 

Manual soak testing involves the testers who manually interact with the system and gradually increase the load for an extended period while monitoring the system’s performance. 

On the other hand, in automated soak testing, automated test scripts will be executed with the help of certain automation tools without the involvement of manual testers. Also, during this approach, testers may use some other third-party tools to evaluate the performance of the system. 

In some cases, both manual and automated approaches are used parallelly to generate the load and evaluate the performance of the software.

The Outcome of Soak Testing

The outcome of soak testing provides valuable insights into the long-term stability of a system or application under sustained stress. It helps identify potential issues such as memory leaks, performance degradation, and stability concerns that may only occur after extended usage. The developers can address the problems that are detected during the test and make the software more stable and reliable.

What are the Common Issues that Soak Testing Detects?

A soak test can reveal several performance-related issues in a software application. Here are some of those common issues.

  • Memory leaks.
  • Performance bottlenecks.
  • Stability issues.
  • Database problems.
  • Caching issues.
  • Unexpected system crashes.
  • Data accumulation.

Several Considerations for Soak Testing

When planning and executing a soak test, several facts should be considered by the software development teams.

  • Duration of the test.
  • The number of scenarios and the generated load.
  • Performance monitoring.

Challenges of Soak Testing

Even though soak tests give a lot of benefits to the development teams it is not a method that has zero challenges. Here are some of them.

  • The huge usage of resources due to the data load.
  • Tests consume a lot of time and effort.
  • Complicated data management.
  • Creation and maintenance of soak test environments.
  • Test automation complexity.
  • Consideration of data privacy and security.

Soak Testing Strategies

Incremental Load Strategy

This involves slowly increasing the load on the system over a long time. Testers start with a minimal load and then incrementally raise it at certain intervals. It’s effective for identifying how the application is slowly growing user demand and helps point out when the issues start to occur.

Steady-State Load Strategy

Here, the load hits the system throughout the test. This is useful for detecting memory leaks and simulating continuous real-world usages.

Variable Load Strategy

In this strategy, fluctuations are applied in the user load during the test. Testers periodically increase and decrease the load and it helps assess how the software adapts to changing usage patterns and whether it can maintain stability and performance under variable loads.

Peak Load Validation

This strategy focuses on assessing how the application performs under peak loads that exceed typical usage conditions. This is important for systems with a high usage in user demand.

Soak testing tools

As we have discussed before, soak tests can be executed both manually and automatically. The following tools can be used when running automated soak tests.

  • Apache JMeter
  • LoadRunner
  • NeoLoad


Soak testing is very important in the process of software testing when it comes to ensuring the performance of systems under huge user load for a long period. It helps the software development teams to identify and fix the system’s performance bottlenecks, memory leaks, and many other hidden issues that can occur. Even though there can be various challenges when executing soak tests, it gives a lot of benefits if the correct tools and techniques are used at the right time.

Frequently Asked Questions

How long is a soak test?

The duration of a soak test can be changed based on the aims, system complexity, and available resources. Soak tests typically run for a minimum of several hours and can extend to a few days or even weeks.

What’s the Difference Between Soak Testing vs. Stress Testing vs. Spike Testing?

Soak testing, stress testing, and spike testing focus on different performance facts of a system’s behavior. Soak testing evaluates a system’s performance under huge loads over an extended period, detecting issues like memory leaks and resource utilization problems. Stress testing aims to evaluate how the application behaves when the loads exceed its normal capacity, identifying the breaking points. Spike testing focuses on assessing the system’s response to sudden and extreme changes in user load.

What are the differences between soak and stress testing?

Soak and stress testing differ in their primary objectives and testing conditions. Soak testing focuses on evaluating a system’s performance with continuous load for a long period. It aims to detect issues like memory leaks and performance bottlenecks. Unlikely to soak testing, stress testing, evaluates how a system performs under overload conditions that exceed its typical operational capacity. It mainly helps to identify the system’s drawbacks.

What are test cases in soak testing?

In soak testing, test cases are specific scenarios and conditions that are designed to simulate continuous usage of a system for a long period. These test cases typically involve gradually increasing the load on the system over time and monitoring various performance parameters. These test cases can be based on actions such as user interactions, data input, and specific workflows.


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