This team focuses on language design and implementation for rich internet applications. There is an increasing demand for web-based services that offer collaborative and off-line functionality. Realizing these qualities brings about a number of essential complexities. This team focusses on aleviating these complexities through novel language abstractions and frameworks. In this field our research advances the state of the art along four main axes. The first axis focusses on the design of tierless programming languages to enable developing the typical server, client and database tiers of a web application as a single mono-linguistic program. The second axis considers maintaining consistency of shared application assets that can be used by clients both off- and on-line. For this topic we advance research on Cloud Types and other eventual consistency mechanisms. A third axis considers safeguarding the security guarantees on the integrity and confidentiality of critical parts of the application data and functionality. For this aspect we focus on programming constructs for implementing confinement-related security policies. A fourth axis considers the specification of constraints on web APIs. There is currently often only a textual version of an API specification. For this work we focus on the development of machine-readable API specification that allows API providers to explicitly list the parameters of a request and their constraints together.