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Monkey Testing: A Guide for Beginners

April 30, 2023
Monkey testing

Monkey testing is a technique in software testing where the tester inputs random data or performs random actions on an application or software to see how the system responds.

By subjecting the software to random input and actions, monkey testing helps ensure that the system is robust enough to handle unexpected scenarios and perform as intended under stress.

Monkey testing implements random and automated unit testing, which can be both manually and automatically executed.

Monkey testing is also known as Random testing, Monkey Testing, or Fuzz Testing, and the technical term is Stochastic Testing.

The tester performs monkey testing in mobile, web, and desktop applications solely based on their gut feeling and mood, without a pre-defined strategy.

How does Monkey Testing work?

In monkey testing, random inputs or actions are given to the software system to test its behavior. These inputs include random data, invalid values, unexpected events, and other unpredictable scenarios. The idea is to test real-world scenarios where users can interact with the software in certain ways.

The tester typically uses a tool or program to generate random inputs or actions through automation. The user can configure the tool to generate a specific number of random inputs or run indefinitely until it meets a specific condition.

The tester then observes the software system’s behavior, looking for unexpected responses, crashes, or other issues. Any issues found are reported back to the development team. 

Features of  Monkey Testing 

In this type of testing, there will be no specifications while performing tests.

  • Teams often implement monkey testing when regular testing processes fail to detect defects or issues.
  • In this testing, the tester acts like a monkey, randomly pressing buttons or inputting data without any particular goal or strategy.
  • The time and effort to test in this type of testing is comparatively lesser than in other types of testing.
  • The main focus of monkey testing is to identify defects or vulnerabilities in a system by randomly inputting data or executing actions, intending to cause the system to crash or fail.
  • Monkey testing is essential for testing high-risk scenarios, such as unexpected user actions or input data.

Types of Monkey Testing  

Types of Monkey testing

There are three major types of Monkey testing, and each focuses on different aspects of the programs and clears bugs from that particular genre: 

  • Dumb Monkey Testing
  • Smart Monkey Testing 
  • Brilliant Monkey Testing

The selection of a particular type of monkey testing depends on the testing objective and characteristics of the system being tested. Every type of monkey testing has its strengths and limitations. 

Therefore, it is essential to evaluate the testing requirements carefully to determine which type of monkey testing would be most appropriate. Several factors may influence the choice of testing, including the system complexity, the type of input data it expects, and the desired level of test coverage.

Ultimately, the goal of monkey testing is to uncover defects or unidentified issues through other types of testing and improve the overall quality and reliability of the software being tested.

Dumb Monkey Testing

Dumb monkey testing is a term used to describe a rudimentary form of monkey testing in which random inputs are generated without any specific knowledge of the application under the test.

In other words, the monkey lacks knowledge of the application and its functioning and could be considered dumb about it.

Dumb monkey testing can be useful as a first step in testing to identify any errors or crashes caused by unexpected inputs.

However, it is not a comprehensive testing method and may not be effective in detecting more complex bugs or issues related to specific features or functions of the application.


The advantages of dumb monkey testing include its simplicity, cost-effectiveness, accessibility to non-technical testers, ability to simulate real-world user interactions, and automation capabilities for large-scale and regression testing. This type of testing is essential for identifying critical defects.


Dumb monkey testing has several disadvantages, including the lack of pre-defined test cases or specifications, which makes it incomplete in covering all possible scenarios. Additionally, it is difficult to reproduce testing results and is unsuitable for complex systems. Moreover, there is a possibility of generating false positives or false negatives. Therefore, Other testing approaches should supplement it to ensure comprehensive test coverage.

Smart Monkey Testing 

Smart Monkey Testing is a variant of monkey testing where the test engineers adopt a more deliberate and attentive approach.

Smart Monkey testing is a technique in which the testing team has knowledge of the software’s functionality and provides appropriate and valid inputs to execute and run the system effectively.

In Smart Monkey Testing, the tester focuses on breaking the system or application under test by inputting intelligent and meaningful data or executing actions that are more likely to expose defects or vulnerabilities.

When a tester finds an error or defect, they should be attentive enough to report the bug with detailed information on how the error occurred, what input or action triggered it, and how the actual behavior of the system differs from the expected behavior.

This type of test gives quicker results, and this is an example of load testing.


The advantages of Smart Monkey Testing include the generation of intelligent and targeted input, prioritization of testing efforts on high-risk areas, customization to specific test scenarios, and automation capabilities for large-scale and regression testing.


Disadvantages of Smart Monkey Testing include requiring a technical understanding of the system, needing more time and resources for development, and the possibility of missing defects outside the targeted areas, highlighting the importance of supplementing it with other testing approaches for comprehensive test coverage.

Brilliant Monkey Testing  

Brilliant monkey testing is the advanced form of monkey testing technique.

A tester or a team of testers will be assigned to the task, ensuring a deep understanding of the software domain and its technologies.

Brilliant Monkey Testing is a more advanced form of monkey testing that involves highly skilled and knowledgeable testers who are one step ahead of Smart Monkey Testing. 

Example: A tester with sufficient knowledge of the eCommerce sector may be requested to input data related to the E-commerce domain.

Benefits of Monkey Testing 

  • There is no need for a skilled tester to perform the monkey testing. Even if the tester has less knowledge about the application, this testing can be rescued.
  • Can quickly classify bugs that may impact the efficiency and performance of the software.
  • Using random data for execution makes it simple.
  • Monkey testing is a testing technique that can be set up and implemented quickly.
  • Monkey testing requires fewer resources to complete testing compared to other types of testing.

Drawbacks of Monkey Testing

  • Monkey testing uses randomly generated test input data, making it difficult to reproduce bugs and errors.
  • The tester cannot assure the accuracy of test cases as they have difficulty defining the exact test scenarios.
  • Testers should have some knowledge of the domain to make monkey testing more accurate.
  • Monkey testing can make the process of evaluating unexpected issues difficult and time-consuming.

Monkey Testing Tools 

Many Monkey testing tools can help make the process of monkey testing easier and more efficient for testers.

Below are the most popularly used monkey testing tools:

MonkeyRunner Tool – Android

Monkey Runner tool can install, execute, and record screenshots on a computer to test Android applications. The tool can also perform random testing and run test suites.

MonkeyRunner is a tool that allows for automated testing of Android applications, including framework-level testing and functional testing. Additionally, it can perform random testing of test suites.

U/I Application Exerciser Monkey – Android

The UI/Application Exerciser Monkey runs in an ADB shell within the emulator or a device, and it is different from Monkey Runner.

It can also generate random stream users and systems, and events.

Monkey testing is a technique designed to generate targeted inputs and actions that are more likely to uncover bugs or issues within the application being tested, as opposed to real monkeys who might randomly press buttons or perform other actions that have no relevance to the testing objectives.

Wrapping Up!

Monkey testing is a type of software testing technique that uses random events to test different aspects of a software application from the user’s perspective. Monkey testing can be both Dumb and Smart Monkeys, with the latter being able to replicate user gestures such as clicks and typing. 

This testing process is suitable for stress testing, ad-hoc testing, and Gorilla testing. While monkey testing is not a part of the standard testing tools, it can still be a good way to get better results for mobile applications. 

The introduction of command-line tools such as App Automate has made monkey testing more accessible for developers and teams. The main objective of monkey testing is to find any system crash or invalid input that may cause issues for end-users. 

The intrinsic randomness of monkeys is the source of the name, and there are different ways to categorize monkey testing. The major difference lies in the state model accuracy and the setup of the testing process. 

Overall, using monkey testing in a software testing process can be highly beneficial, particularly in today’s marketplace where products require comprehensive testing before release.

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