PyCon India 2025

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Compiling Python to WASM
.ical
2025-09-13 –, Track 3

Python is one of the most popular programming languages in the world. But when it comes to running in the browser, it still lags behind. Existing solutions like Pyodide and RustPython attempts to bridge the gap using CPython or transpilation, but they come with significant trade-offs: large payload sizes, slow startup times, and compatibility constraints.

This talk explores the current Python + WebAssembly (WASM) ecosystem and its limitations. We’ll look at how projects like Pyodide, PyScript, and RustPython attempt to make Python web-native and why they fall short. Then, we’ll dive into why a native Python-to-WASM compiler is the missing piece and how such a compiler could radically improve performance, portability, and adoption.

We wrote a native python to wasm compiler, called Waspy, which we'll talk about and how various python components and types are compiled and placed.

  1. Introduction (3 mins)
    - The rise of WebAssembly: performance + portability
    - Python’s popularity vs its absence in web-native environments

  2. The State of Python on the Web Today (7 mins)
    - Overview of major approaches:
    - Pyodide (CPython compiled to WASM)
    - PyScript
    - RustPython on WASM
    - Pros and cons of each approach
    - Benchmarking for each

  3. Why These Solutions Fall Short (4 mins)

  4. Making the Case for a Native Python-to-WASM Compiler (8 mins)
    - What “native” compilation means
    - Benefits
    - Current Solution: py2wasm with small demo of compiling and running using a wasm runtime.

  5. Waspy (4 mins)
    - Where py2wasm falls short
    - Why we need a pure python to wasm native compiler

  6. Closing Thoughts and Call to Action (2 mins)
    - A vision for Python as a first-class citizen in the browser
    - Call for contributors and researchers
    - Q/A

Target Audience –

Beginner
See also: Project Repo
The speaker’s profile picture
Kumar Anirudha

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The speaker’s profile picture
Farhaan Bukhsh

Farhaan Bukhsh is an open-source contributor, Pythonista and now a newbie rustacean. With a background in cloud infrastructure and platform engineering, Farhaan has contributed extensively to projects like Fedora and Open edX, where he is a core committer and current release manager. He's passionate about bridging the performance gap between Python and system-level programming, recently exploring the power of Rust to accelerate machine learning workflows. When he's not writing code, Farhaan enjoys mentoring new contributors, organizing tech communities, and brewing the perfect pour-over coffee.