Variables and Environments in Postman

Postman’s capabilities extend beyond basic API requests. It empowers you to work with variables and environments, enabling dynamic and context-aware testing and development. In this guide, we will introduce you to the concept of variables and how to use environments to manage them effectively.

Introducing Variables

Variables in Postman serve as placeholders for dynamic values that can change during testing or development. They offer flexibility and reusability, making it easy to work with different data sets, configurations, or environments. Postman supports various types of variables:

1. Global Variables:

  • Global variables are accessible across all collections, requests, and environments.
  • They are ideal for storing data that remains consistent throughout testing.

2. Environment Variables:

  • Environment variables are specific to a defined environment.
  • They are excellent for managing variables that differ between development, testing, and production environments.

3. Local Variables:

  • Local variables are only available within a specific request or script.
  • They are useful for temporary variables or data that should not affect other parts of your workflow.

Using Variables in Postman

Variables in Postman are enclosed within double curly braces, like {{variable_name}}. Here’s how you can use them:

Setting Variables

  1. Creating Variables: You can create variables in the Postman app by clicking on the “Manage Environments” option and defining variables in the “Quick Look” or “Edit” section of the selected environment.
  2. Defining Initial Values: Assign initial values to variables, specifying what they represent, such as API endpoints, authentication tokens, or any dynamic data.

Accessing Variables

  1. Referencing Variables: To use a variable in your requests or scripts, enclose its name within double curly braces. For instance, if you have a variable named baseURL, you can use it as {{baseURL}} in your request URL.
  2. Dynamic Data: Variables enable you to work with dynamic data, such as changing API endpoints or authentication tokens based on the environment.

Changing Variable Values

  1. Updating Variables: You can change the value of a variable within an environment. The new value will then apply to all requests using that variable.
  2. Scripting and Tests: Variables can be updated programmatically within scripts and tests, allowing for dynamic behavior during request execution.

Environments in Postman

Environments provide a structured way to manage variables. They group related variables together, making it easy to switch between different sets of values for testing or development.

Creating Environments

  1. Defining Environments: You can create environments in Postman by clicking on the “Manage Environments” option and adding a new environment with a name and associated variables.
  2. Assigning Environments: Associate specific requests or collections with an environment to ensure they use the environment’s variables.

Switching Environments

  1. Environment Dropdown: Postman offers an environment dropdown that allows you to select the active environment. The variables associated with the selected environment are used in your requests.
  2. Dynamic Environment Switching: You can switch environments dynamically using scripts or pre-request scripts, enabling conditional behavior based on the active environment.

Conclusion

Variables and environments in Postman are invaluable tools for working with dynamic data and managing different testing or development scenarios. They provide flexibility, reusability, and context-awareness, enhancing your testing and development capabilities.