After you have recorded and tried out your script for the first time, you may need to customize it for two reasons:
The script does not replay without errors.
Session-specific data that was captured during recording is usually not valid during replay. This is because data like session IDs change every time a new communication session is started with the application under test. Session-specific data can be represented by variables and is, consequently, dynamically adjusted during each run. This leads to clean scripts that work flawlessly every time they are executed.
You want to introduce more variety in virtual user behavior.
The virtual users will behave identically during your load test, unless you introduce data or environmental variation, such as simulating different browsers, bandwidths, or paths through the application.
Therefore, it is recommended to customize your scripts before you start a load test. Customizing scripts offers the following advantages:
Your virtual users will be diverse.
For example, you can set them up to use different browsers and bandwidths from different locations to access the application under test.
Your virtual users will behave more realistically and more natural.
This can be achieved with randomized data. The virtual users will then, for example, input varying data in forms, like different names, addresses, and credit card numbers. They can vary the product names they search for, the products they order, and so on. This leads to accurate and meaningful result data.
Customizing scripts is typically done before you move on with the next step in the workflow bar.