Parameterized Load Test

Creating a load test by using parameters and extracting response values

In our first simple test we have simulated users loading the homepage of our blog, our second test is going to simulate several users publishing new entries to the blog.

  • First create a new empty test. Only logged in users can post to our blog, so let's start by executing a login request and store the authentication token returned by it into a parameter for later use.

  • Give your new test a short description Login & Create a blog post

  • Update the request description to Blog Login

  • Set the Request #1 method to POST and its URL to -

  • Click the "ADVANCED" button to expand the advanced section of the request.

  • Set the Content-Type to application/x-www-form-urlencoded (last in the list).

  • And paste this as the request body - grant_type=password&

  • Expand the “Extractions - Set Parameters” card and set a value to a parameter named access_token using a JSONPath extractor querying for access_token. This will create a value extractor that will execute a JSONPath query against the JSON response of the request and extract the authentication token into a parameter named access_token.

  • Verify that a value was set to the parameter access_token by the JSONPath extractor by expanding the ‘Verify Response’ card of the request and creating an assertion. Add an assertion that states that the access_token parameter Is True (Use the "Exists" assertion type).

  • Click DRY RUN and execute a trial run to make sure it is working.

  • Now that we have the authentication token stored in access_token we can use it to publish on our blog

    • Create a new request by clicking the "+ ADD REQUEST" button below the first request.

    • Set its description to Publish Blog Post

      Set it as a POST request to

    • Click on the "ADVANCED" button and set the Content-Type to application/json and the body to this JSON-

       "posts": [
             "title": "Title ${__random_chars}",
             "slug": "${__random_chars}",
             "markdown": "Text ${__random_chars}",
             "status": "published"
    • This JSON body defines the blog post that we are going to publish. Notice that we have used one of Loadmill's functions to make it a little more interesting - ${__random_chars}. The __random_chars parameter will change to 10 random characters during test/trial execution.

    • Now, let's use the access_token parameter value we extracted from the login response to authenticate this request. Expand the header card of publish request and add a header with the name Authorization and the value Bearer ${access_token}

    • Run a trial of the whole scenario and go to to see that our blog posts are getting published.

Now that we know that our full scenario is working we can run it as a load test. Click the "RUN TEST" button at the bottom of the test and run the test 🎉

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