Software testing and web service testing are necessary because errors and failures happen to all of us, and some mistakes happen because of false presuppositions, so it’s advisable for others to validate software too so that errors could be avoided. According to definition, software testing is process of analysis of software elements so that we can determine a difference between existing state and requirements and so that software characteristic could be established. It is better to do testing sooner than later because if failures are founded in earlier phases than costs of repair are significantly lower. Web service is software system that is designed in a way that it supports machine to machine interaction over network. Results of web services testing show what functions does web service enable, which features does it support and how much capabilities can be used. The most popular ways of data transfer between web services are over REST and SOAP messages. In order to fix failures of traditional software development, software engineers have over time designed new way of software development, Test-Driven Development. It has some significant advantages over traditional testing and development because tests are written and run from the mere beginning of a project so that it is easier to handle errors, but still it has some disadvantages. Because of TDD failures like not good enough answers on questions like what and when to test and how to name tests in the best way, Behavior-Driven Development was developed. BDD is upgraded and improved TDD and has a lot of advantages, but of course it also has its own failures. One of the most popular and most used tool for BDD is Cucumber which is used, except for BDD, also for software testing and web service testing. Development in Cucumber starts with choosing features and then writing scenarios, wanted behavior models in Gherkin language. That language is specific because it is very similar to human natural language so it is understood not only by software engineers, but also business clients. After that, we define step definitions that we need to implement so that scenario could be successfully executed. Step definitions are usually implemented in Ruby language. Comparing programs and applications developed in a traditional way with those developed in Cucumber with BDD methodology, advantages and disadvantages of BDD over traditional development are determined and described.