This thesis presents the development of a comprehensive web-based health tracking application, Healthify, designed to integrate multiple health information into a single platform. It integrates with the Fitbit API to deliver users data regarding their workouts, daily steps, and calories burned. The architecture of the application is built on a client-server pattern. The frontend is developed using JavaScript, which allows for dynamic and interactive user interfaces. It utilizes the Fitbit API to fetch user-specific health data, enabling the application to present detailed information about workouts, daily steps, and calories burned. On the backend, the application utilizes Node.js paired with the Express framework to create a robust server that handles client requests and serves responses efficiently. MongoDB serves as the database management system, providing a flexible schema for storing user data. To facilitate interactions with the database, the Mongoose library is employed, allowing for the definition of schemas and models. This simplifies database operations, enabling the application to perform Create, Read, Update, and Delete (CRUD) operations seamlessly for user data. This work includes a comprehensive review of existing health applications, highlighting their features and approaches, as well as an exploration of the sensors used in fitness wearables. The thesis also discusses the strengths and weaknesses of various programming languages and architectures, contributing to a deeper understanding of the technologies involved.