What is Gherkin?
Gherkin is a business-formatted DSL (Domain Specific Language) that is used to describe how somethings behaves without actually implementing that functionality.
The format for a Gherkin file is done by defining a Feature, then a Scenario.
Feature: Describe what this feature is about. Scenario: Describe what the scenario will be about. Given I do something And do something else When this happens Then I get to do something new
Why would you ever want to write the Gherkin? In a business format, the Gherkin file can be used in a variety of ways. One of those ways is to have a common language between the developer and the business. A business-minded person can use this format to describe a behavior that they would like out of the product. Or the reverse can be true: a developer can describe the functionality that they will be implementing so the business person can understand.
Now that I have this Gherkin file, what can I do with it besides communicate with the business people? Once you have a behavior in mind that you need, you can start the BDD process. Write some step definitions to test your new application based on the description on the DSL, then write code to make it pass that behavior.
Once you have written the steps and built your application based on those tests, now you will have living documentation for your application. Depending on the framework and language you use, you can create some interesting artifacts to go along with the Gherkin. For example, by automating these tests you can record the video of functionality or capture screenshots to help describe what is going on. These tools can be quite valuable to a new user of your application or maybe a new team member. As long as you keep up with your tests then you should have current and reliable documentation for you application.