Implementing web applications in an object-oriented language such as Java using state-of-the-art frameworks produces robust software, but involves a lot of boilerplate code. (DSLs) replace boilerplate code by high-level models, from which code can be generated. This tutorial shows how to find domain-specific abstractions based on patterns in existing (reference) programs and build domain-specific languages to capture these abstraction using several DSLs for DSL engineering: SDF for syntax definition and Stratego/XT for code generation. The approach is illustrated using the design and implementation of WebDSL, a domain-specific language for web applications, which provides abstractions for data models, page definitions, access control, workflow, and styling. * WebDSL: A Case Study in Domain-Specific Language Engineering * Code Generation by Model Transformation * Domain-Specific Language Engineering. A Case Study in Agile DSL Development