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Table of contents
About JMeter Test Plan
Commonly used JMeter Assertions
Response Assertion
Duration Assertion
Size Assertion
XML Assertion
HTML Assertion
BeanShell Assertion
Frequently Asked Questions
What purposes do JMeter Assertions serve?
JMeter employs which programming language?
In JMeter, what does JSON Assertion mean?
Can we add an Assertion to any Sampler?
Last Updated: Mar 27, 2024

How to use Assertions in JMeter?

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Hello Techies!

Let’s say we must test a web server and check how many concurrent users it can handle. For that, we need a performance testing tool that generates and simulates many concurrent user loads on the web server. So are you also thinking that Apache Jmeter will be the suitable tool? Then yes, this is where Apache Jmeter comes to the rescue!

Introduction to assertions in Jmeter

It is an open-source load and performance testing software based on Java Language. It was primarily written to load and test the performance of Apache JServ (also called the Apache Tomcat project). Later on, to add more features and functional testing capabilities, the Apache community redesigned it to enhance the GUI. This blog will focus specifically on “Assertions,” an element of the JMeter Test Plan.

About JMeter Test Plan

A test plan is your JMeter script for running tests. Components like the Thread groups, logic controllers, controllers, listeners, timers, Assertions, and configuration elements comprise a test plan.

JMeter logo


A test plan includes all of the steps required to run the script. Everything in a test plan is executed in a top-to-bottom sequence or according to the test plan's defined sequence. The diagram below depicts the directory level of a test plan.

Jmeter Test Plan components


Points to note on a Test Plan - 

  • Before running the entire test plan, the test plan is saved.
  • JMeter files or test plans are saved in the ‘.JMX’ extension. JMX is an open test format that allows the test plan to run in a text editor.
  • Parts of the test plan can also be saved as a different selection. For example, if you want to save an HTTP request Sampler with a listener, you can save it as a test fragment and use it in other test scenarios.

Test Plan window

The above image shows the JMeter Window.

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In JMeter, the Assertion is used to validate the response to the request you sent to the server. At run time, the Assertion is a process in which you compare the expected result to the actual result of the request. If you need to apply Assertion to a specific Sampler, make it a child of that Sampler. The image below shows how to add an Assertion to your JMeter Test Plan.

Adding Assertion to Test Plan

Below given is the list of all the Assertions JMeter provides −

  • Response Assertion
  • Duration Assertion
  • Compare Assertion
  • Beanshell Assertion
  • BSF Assertion
  • JSR223 Assertion
  • BeanShell Assertion
  • MD5Hex Assertion
  • HTML Assertion
  • XPath Assertion
  • Size Assertion
  • XML Assertion
  • XML Schema Assertion
  • SHMIME Assertion
  • JSON JMESPath Assertion

As we can see, many Assertions are used in JMeter but don’t get intimidated. Only a few of them are used commonly, and we will look into them in detail.

Commonly used JMeter Assertions

This section will discuss the need and way to use the most frequently used Assertions in a JMeterTest Plan. Let us explore them one by one.

Response Assertion

We use response Assertions to check the patterns in the server's response body. Various pattern-matching rules, such as contains, matches, equal, etc., can be applied to validate the response. These comprise the response Assertion's fundamental components.

Response Assertion Window

Duration Assertion

The Duration Assertion measures the speed with which each server response was obtained. Any response that takes more than the user-specified number of milliseconds is labeled as a failed response.

Duration Assertion Window

The image above shows the duration Assertion window.

Size Assertion

The expected number of bytes is confirmed using the size Assertion method. We can provide the anticipated size in bytes and check using various comparisons like >,<, =, etc. The following elements make up JMeter's Size Assertion.

Size Assertion Window

XML Assertion

This Assertion is used to determine whether or not the XML document returned by the server is accurate.XML Assertion Window

 These are the fundamental components of an XML Assertion.

HTML Assertion

This Assertion is used to validate the HTML provided by the server as part of the response. The essential parts of the HTML Assertion are listed below.

HTML Assertion Window

BeanShell Assertion

We can validate the results of a Sampler using BeanShell Scripting and the BeanShell Assertion. The following are the fundamental components of a BeanShell Assertion in JMeter.

BeannShell Assertion Window


Must Read Apache Server

Frequently Asked Questions

What purposes do JMeter Assertions serve?

JMeter uses Assertions to verify the server's response to your request. The Assertion is a technique to compare the request's actual outcome to what was anticipated at run time. If an Assertion needs to be applied to a specific Sampler, add it as a child of that Sampler.

JMeter employs which programming language?

JMeter uses the Groovy language as a scripting language. Groovy has proven to be a powerful yet lightweight language in terms of performance in improving JMeter's functionality.

In JMeter, what does JSON Assertion mean?

The Response Assertion has been extended to include JSON. It seeks to make it easier to navigate JSON answers so that data integrity checks can be completed quickly. JMeter will throw an error if the JSON path specified in the Assert JSON Path exists parameter does not exist.

Can we add an Assertion to any Sampler?

Yes. We can add Assertions to any Sampler.


This blog discussed Assertions in JMeter, an important element of the JMeter Test Plan. We started by discussing the JMeter test Plan and then discussed the JMeter Assertion and its types. We hope this blog added to your knowledge of JMeter.

For more information on JMeter, Refer to our other articles-


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