The proposed talk will review progress on the Hazel programming environment and its underlying theoretical developments. Hazel is the first totally live typed general-purpose programming environment, meaning that it deploys error localization and recovery mechanisms, rooted in language-theoretic developments, that ensure that every editor state is syntactically well-structured and statically and dynamically meaningful. The talk will review the underlying theory and include a live demonstration of Hazel’s various features. Hazel has been deployed in an educational setting, and we will review both the educational technology aspects and the preliminary results of using Hazel with humans for the first time. The talk will also discuss various ongoing and future directions.