Cucumber is a software tool that supports behavior-driven development (BDD). Central to the Cucumber BDD approach is its ordinary language parser called Gherkin. It allows expected software behaviors to be specified in a logical language that customers can understand. As such, Cucumber allows the execution of feature documentation written in business-facing text. It is often used for testing other software. It runs automated acceptance tests written in a behavior-driven development (BDD) style.
Cucumber was originally written in the Ruby programming language and was originally used exclusively for Ruby testing as a complement to the RSpec BDD framework. Cucumber now supports a variety of different programming languages through various implementations, including Java and JavaScript. There is a port of Cucumber to .NET called SpecFlow, now superseded by Reqnroll.