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Mesop: Build delightful web apps quickly in Python 🚀

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Used at Google for rapid internal app development

Mesop is a Python-based UI framework that allows you to rapidly build web apps like demos and internal apps:

Intuitive for UI novices ✨

  • Write UI in idiomatic Python code
  • Easy to understand reactive UI paradigm
  • Ready to use components

Frictionless developer workflows 🏎️

  • Hot reload so the browser automatically reloads and preserves state
  • Rich IDE support with strong type safety

Flexible for delightful demos 🤩

  • Build custom UIs without writing Javascript/CSS/HTML
  • Compose your UI into components, which are just Python functions

Write your first Mesop app in less than 10 lines of code...

Demo app

import time

import mesop as me
import mesop.labs as mel"/text_to_text", title="Text I/O Example")
def app():
    title="Text I/O Example",

def upper_case_stream(s: str):
  yield s.capitalize()
  yield "Done"

Try it


You can try Mesop on Colab!


Step 1: Install it

$ pip install mesop

Step 2: Copy the example above into

Step 3: Run the app

$ mesop

Learn more in Getting Started.


This is not an officially supported Google product.