The Defensics Suite Development Kit (SDK) is a framework for creating custom model-based fuzzers that can be deployed just like our commercially available pre-built suites. The Defensics SDK was developed to support Defensics users who require more granular control of their test suite configurations, or who need to test applications or devices that employ uncommon, customized, or proprietary protocols and interfaces. With the Defensics SDK, you can develop test suites that fit your particular needs. You can create a custom model for the inputs that you wish to fuzz, control the delivery of test cases to a target, determine if a target has failed, and influence the flow of the fuzzer. The suite created using Defensics SDK generates test cases based on custom created BNF model and custom functional logic implemented in Java programming language. The same SDK API is used internally to create our commercially available pre-built suites, so it is well-maintained and very powerful.