PyScript, which is, of course, Python in the browser. The tool is in the early experimental phase, so the project doesn’t suggest using it in a production environment yet.

Playwright, a Python library, allows developers to essentially control the browser with a few lines of Python code to automate cross-browser testing for single-page web apps and Progressive Web Apps.

A new project from Anaconda delivers the Python runtime in a web page, via a single JS include, and with access to many popular Python packages.

Microsoft plans to enable the Python and Ruby languages to be used for client-side development of rich Internet applications that leverage the company’s Silverlight browser plug-in technology ...

Guido van Rossum, the creator of the hugely popular Python programming language, has given his thoughts on the language for the browser, mobile devices, and upcoming rivals like Julia.

It's possible to take a step further with a browser extension, but this is a basic Python project that hosts a web page that you can drag and drop a file on for a visualizer.