reflex-dev/reflex

Reflex is a Python framework that lets you build full-stack web applications, both the user interface and the backend logic, entirely in Python, without writing any JavaScript. This is useful for developers who know Python well but want to create interactive web apps without learning a second language. The framework works by letting you define your app's visual interface using Python functions and components (like buttons, inputs, and layouts), while a separate "State" class holds all the data that can change as users interact with the app. When a user clicks a button or types something, "event handlers" (regular Python methods) update the state, and the UI automatically re-renders to reflect those changes. Reflex handles the connection between the frontend (what users see in their browser) and the backend (your Python server) automatically. The README includes a complete working example: a single-file image generation app that connects to an external AI image service. The example shows how UI components nest together, how state variables track things like loading status and results, and how event handlers respond to user clicks. This demonstrates that fairly rich apps can be written in a single Python file. Reflex supports over 60 built-in UI components and can be deployed with a single command. It requires Python 3.10 or newer. You would use it when you want to build dashboards, data visualization tools, internal tools, or other web interfaces using pure Python, especially if you are a data scientist or backend developer who wants to avoid learning frontend frameworks. The full README is longer than what was provided.