In Multi-Step API monitoring, you can use the available automatic variables to generate dynamic data, including random GUIDs, random numbers, and dynamic dates and times. However, every time you use such a function in your request, it will generate a new value. What if you want to generate it once, and use that same value in multiple steps? You can now use automatic variables in your predefined variable definitions. Predefined variables are the variables that you define upfront and will be evaluated right before the multi-step scenario starts. The variables essentially become fixed values that are available throughout all steps in your scenario.
But that’s not all! All variables (predefined variables, variables you define in individual steps, and even automatic variables) can now be used inside your assertions as well. This means that if you have an HTTP response and you want to check its content against a variable you defined earlier, you can do that. You can use a variable reference in an assertions' target value, or even include it as part of an XPath query or JSON expression.
For more information, please read the Multi-Step API variables documentation.