What is System Testing? Types with Example

What is System Testing?

System Testing is a level of testing that validates the complete and fully integrated software product. The purpose of a system test is to evaluate the end-to-end system specifications. Usually, the software is only one element of a larger computer-based system. Ultimately, the software is interfaced with other software or hardware systems. System Testing is defined as a series of different tests whose sole purpose is to exercise the full computer-based system.

The diagram above illustrates the core dimensions a tester inspects during System Testing, including functional flows, user interfaces, data handling, and integration points. This level of testing sits immediately after Integration Testing and before User Acceptance Testing in the software testing life cycle.

System Testing Video Explanation

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Why is System Testing Important?

Unit and Integration tests examine code fragments and their interfaces, but they cannot prove that hardware, software, network, and configuration elements cooperate as one product. System Testing closes that gap and secures the software before release.

Key reasons this phase is indispensable include:

• End-User Confidence: Verifies that real-world workflows behave as business requirements specify, reducing post-release defects.
• Risk Reduction: Uncovers integration, performance, and environment issues before production, preventing costly outages.
• Compliance Assurance: Regulated industries such as finance, healthcare, and aviation require documented System Testing evidence.
• Cost Efficiency: Fixing defects at this stage is far cheaper than addressing them after release.
• Acceptance Readiness: A clean System Test creates a stable baseline for User Acceptance Testing.

What do you verify in System Testing?

System Testing involves testing the software code for the following purposes:

• Testing the fully integrated applications including external peripherals to check how components interact with one another and with the system as a whole. This is also called End-to-End testing scenario.
• Verify thorough testing of every input in the application to check for desired outputs.
• Testing the user’s experience with the application.

That is a very basic description of what is involved in system testing. You need to build detailed test cases and test suites that test each aspect of the application as seen from the outside without looking at the actual source code. To learn more about a comprehensive approach to this process, consider reading about end-to-end testing.

System Testing is Black Box Testing

Software Testing can be broadly categorized into two types:

• Black Box Testing
• White Box Testing

System Testing falls under the black box testing category of Software testing. White box testing is the testing of the internal workings or code of a software application. In contrast, black box or System Testing is the opposite. System testing involves the external workings of the software from the user’s perspective.

Software Testing Hierarchy

As with almost any software engineering process, software testing has a prescribed order in which things should be done. The following is a list of software testing categories arranged in chronological order. These are the steps taken to fully test new software in preparation for marketing it.

As shown in the hierarchy above, System Testing sits between Integration Testing and Acceptance Testing, making it the final technical validation before the product reaches end users.

• Unit Testing is performed on each module or block of code during development. Unit Testing is normally done by the programmer who writes the code.
• Integration Testing is done before, during, and after integration of a new module into the main software package. This involves testing of each individual code module. One piece of software can contain several modules which are often created by several different programmers. It is crucial to test each module’s effect on the entire program model.
• System Testing is done by a professional testing agent on the completed software product before it is introduced to the market.
• Acceptance Testing is the beta testing of the product done by the actual end users.

Types of System Testing

There are more than 50 types of System Testing. For an exhaustive list of software testing types click here. Below we have listed the types of system testing a large software development company would typically use:

• Usability Testing mainly focuses on the user’s ease of using the application, flexibility in handling controls, and the ability of the system to meet its objectives.
• Load Testing is necessary to know that a software solution will perform under real-life loads.
• Regression Testing involves testing done to make sure none of the changes made over the course of the development process have caused new bugs. It also makes sure no old bugs appear from the addition of new software modules over time.
• Recovery Testing is done to demonstrate that a software solution is reliable and trustworthy, and that it can successfully recover from possible crashes.
• Migration Testing is done to ensure that the software can be moved from older system infrastructures to current system infrastructures without any issues.
• Functional Testing – also known as functional completeness testing, this involves trying to think of any possible missing functions. Testers might make a list of additional functionalities that a product could have to improve it during functional testing.
• Hardware/Software Testing – IBM refers to Hardware/Software testing as "HW/SW Testing". This is when the tester focuses his or her attention on the interactions between the hardware and software during system testing.

What Types of System Testing Should Testers Use?

There are over 50 different types of system testing. The specific types used by a tester depend on several variables. Those variables include:

• Who the tester works for – This is a major factor in determining the types of system testing a tester will use. Methods used by large companies are different than those used by medium and small companies.
• Time available for testing – Ultimately, all 50 testing types could be used. Time is often what limits us to using only the types that are most relevant for the software project.
• Resources available to the tester – Of course, some testers will not have the necessary resources to conduct a testing type. For example, if you are a tester working for a large software development firm, you are likely to have expensive automated testing software not available to others.
• Software Tester’s Education – There is a certain learning curve for each type of software testing available. To use some of the software involved, a tester has to learn how to use it.
• Testing Budget – Money becomes a factor not just for smaller companies and individual software developers but large companies as well.

Best System Testing Tool

Selecting the right platform can dramatically reduce the effort required to plan, execute, and maintain system-level test suites. The tool listed below stood out during hands-on evaluation for coverage breadth, automation quality, and integration flexibility.

1) Testsigma

Testsigma is a comprehensive cloud-based system testing platform I have found essential for automating complete end-to-end user journeys across multiple modules, technologies, and application layers. It is specifically designed for teams that need to validate that their entire system functions cohesively before release, ensuring all components work together seamlessly in real-world scenarios.

During my system testing initiatives, I used Testsigma’s unified approach to chain complex workflows spanning web interfaces, mobile applications, and backend APIs within single test scenarios. The platform’s ability to orchestrate multi-technology test flows gave me confidence that cross-module interactions remained stable, while detailed execution logs and visual reports helped me quickly identify and resolve system-level failures at integration boundaries.

Features:

• Multi-Step Cross-Technology Test Chaining: Build scenarios that connect steps across pages, services, and application types. You can orchestrate web, mobile, and API validations in one sequence to replicate authentic user journeys.
• Unified Web, Mobile, and API Test Execution: Combine UI steps with backend service validations in the same scenario. You can verify that frontend actions trigger correct API calls and produce the expected system responses.
• Reusable System-Level Flow Components: Create modular blocks for end-to-end workflows that recur across tests. You can reduce duplication and accelerate development, with support for parameterization and conditional logic.
• Pre-Release CI/CD Integration: Testsigma executes system tests automatically before releases. You can configure quality gates, schedule validation runs, and block deployments based on results through webhooks and DevOps tools.

Pros

• Validates realistic end-to-end behavior across the entire system.
• Unified tooling for UI and API steps simplifies system-level automation workflows.
• Strong reporting helps teams quickly trace failures and dependencies across multiple modules.

Cons

• Complex system flows often require thoughtful test design, ongoing maintenance, and deeper domain understanding.

Pricing:

• Price: Custom pricing tailored to system test execution scale, team adoption, and organizational requirements.
• Free Trial: 14-Days Free Trial

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