This application allows users to create reusable dynamic blocks for Twilio SendGrid Dynamic Templates. It provides a user-friendly interface for designing and updating templates, as well as storing and importing block structures. The app uses React, Redux, and Twilio Serverless functions to manage state and interact with the SendGrid API. It includes features such as HTML sanitization, DOMPurify, and jsZip for uploading zip files and processing images. The application also includes a folder structure management system, allowing users to organize and export their blocks in JSON format. Extensibility is possible through the use of variables.js, which defines components with fields and styles that can be extended or modified.