gladius

Gladius aka "gladius" is a library facilitating web application development exclusively in pure Python, eliminating the need for HTML, CSS, or JavaScript/TypeScript.

Built for developers who want to leverage Python across the entire stack, Gladius provides access to modern web framework features while mirroring patterns familiar to full-stack Python developers. These developers often blend Python on the server with traditional JavaScript/CSS tools for frontend UI—Gladius simplifies this workflow by enabling Python-driven UI development, reducing context-switching between languages.

For traditional frontend developers, Gladius offers a comfortable transition by exposing all standard Web APIs available in browsers. This ensures compatibility with existing NPM packages (from npmjs), allowing seamless integration of JavaScript libraries when needed.

By unifying frontend and backend development under Python, Gladius delivers a cohesive, intuitive experience—ideal for developers seeking a Python-centric approach without sacrificing access to the broader web ecosystem.

Install

pip install gladius[all]

Hello World

Create app.py file with content:

from aiohttp import web
from gladius.starter import create_aiohttp_app

# required npm packages
npm_packages = {
    '@picocss/pico': ['css/pico.css'],
    'nprogress': ['nprogress.js', 'nprogress.css'],
}

# client-side click handler
def ready():
    from pyscript import when
    from pyscript.web import page
    from pyscript.js_modules.nprogress import default as NProgress

    btn = page['#hello-button'][0]  # get server-created button
    clicked = 0                     # track clicks

    @when('click', btn)
    def on_click(event):
        global clicked
        NProgress.start()
        clicked += 1
        btn.innerText = f'Clicked {clicked} time{"s" if clicked !=1 else ""}!'
        NProgress.done()

# create simple aiohttp web server
g, page, app = create_aiohttp_app(
    npm_packages=npm_packages, # type: ignore
    use_pyscript=True,
    use_micropython=True,
    ready=ready,
)

# server-side structure
with page:
    with g.body(x_data=None):
        with g.main(class_='container'):
            g.h1('Gladius Demo')
            g.button('Click me!', id='hello-button')    # create button on server

# start application
if __name__ == '__main__':
    web.run_app(app, host='0.0.0.0', port=5000)

Run python app with simple server in background:

python -B app.py

Or, in case you want to rebuild on code change:

python -B -u -m gunicorn --reload --bind '0.0.0.0:5000' --timeout 300 --workers 1 --worker-class aiohttp.GunicornWebWorker 'app:app'