The MongoDB Web Shell is a web-based application designed to emulate some of the features of the mongo terminal shell, providing a responsive command line interface similar to the desktop shell. The user interfaces with the backing mongod instance through a RESTful interface implemented on top of Flask, allowing for sandboxing capability and preloading data into resources. A key challenge was allowing blocking paradigm code without blocking in the web browser, which was addressed by using a Javascript evaluator that can pause execution at any time. The shell will be used to replace the existing browser shell on try.mongodb.org, provide better support for JavaScript syntax and MongoDB features, and make its debut on the 10gen Education platform, where users can complete assignments entirely within the education platform without needing to download and install their own copy of MongoDB or sample data. Additionally, it will be embedded into the API reference pages as part of the database's documentation, allowing users to test commands and evaluate effects against provided sample data sets. The project is Apache licensed open source software, freely available through a Github repository.