Abstract-Computer science researchers in the programming languages and formal verification communities, among others, have produced a variety of automated assistance and verification tools and techniques for formal reasoning. While there have been notable successes in utilizing these tools on the development of safe and secure software and hardware, these leading-edge advances remain largely underutilized by large populations of potential users that may benefit from them. In particular, we consider researchers, instructors, students, and other end users that may benefit from instant feedback from lightweight modeling and verification capabilities when exploring system designs or formal arguments.We describe Aartifact, a supporting infrastructure that makes it possible to quickly and easily assemble interacting collections of small domain-specific languages, as well as translations between those languages and existing tools (e.g., Alloy, SPIN, Z3) and techniques (e.g., evaluation, type checking, congruence closure); the infrastructure also makes it possible to compile and deploy these translators in the form of a cloud-based web application with an interface that runs inside a standard browser. This makes more manageable the process of exposing a limited, domainspecific, and logistically accessible subset of the capabilities of existing tools and techniques to end users. This infrastructure can be viewed as a collection of modules for defining interfaces that turn third-party formal modeling and verification tools and techniques into plug-ins that can be integrated within web-based interactive formal reasoning environments.