— We present Bristlecone, a programming language for robust software systems. Bristlecone applications have two components: a high-level organization specification that describes how the application’s conceptual operations interact, and a lowlevel operational specification that describes the sequence of instructions that comprise an individual conceptual operation. Bristlecone uses the high-level organization specification to recover the software system from an error to a consistent state and to reason how to safely continue the software system’s execution after the error. We have implemented a compiler and runtime for Bristlecone. We have evaluated this implementation on three benchmark applications: a web crawler, a web server, and a multi-room chat server. We developed both a Bristlecone version and a Java version of each benchmark application. We used injected failures to evaluate the robustness of each version of the application. We found that the Bristlecone versions of ...