Tavor (Sindarin for woodpecker) is a framework for easily implementing and using fuzzing and delta-debugging. Its EBNF-like notation allows you to define file formats, protocols, and other structured data without the need to write source code. Tavor relaxes on the definitions of fuzzing and delta-debugging to enable the usage of its algorithms universally for keyword-driven testing, model-based testing, simulating user-behavior and genetic programming. Tavor is also well-suited for researching new methods without reimplementing basic algorithms.We want to test a service which processes an XML structure. The structure can contain groups and items. A group contains other groups or items. An Item consists of an attribute name with an alphanumeric value. The item's value contains a number. This structure sounds simple but allows an enormous variety of possible outcomes. It is therefore hard to test since a tester has to think about every important possibility if the generation of the test data is done manually. Doing this manually is cumbersome and error-prone. Tavor can be used to automate the generation.