Simon Willison’s Weblog

experimental-phi3-webgpu (via) Run Microsoft’s excellent Phi-3 model directly in your browser, using WebGPU so didn’t work in Firefox for me, just in Chrome.

It fetches around 2.1GB of data into the browser cache on first run, but then gave me decent quality responses to my prompts running at an impressive 21 tokens a second (M2, 64GB).

I think Phi-3 is the highest quality model of this size, so it’s a really good fit for running in a browser like this. # 9th May 2024, 10:21 pm

Figma’s journey to TypeScript: Compiling away our custom programming language (via) I love a good migration story. Figma had their own custom language that compiled to JavaScript, called Skew. As WebAssembly support in browsers emerged and improved the need for Skew’s performance optimizations reduced, and TypeScript’s maturity and popularity convinced them to switch.

Rather than doing a stop-the-world rewrite they built a transpiler from Skew to TypeScript, enabling a multi-year migration without preventing their product teams from continuing to make progress on new features. # 4th May 2024, 2:08 pm

Introducing Enhance WASM (via) “Backend agnostic server-side rendering (SSR) for Web Components”—fascinating new project from Brian LeRoux and Begin.

The idea here is to provide server-side rendering of Web Components using WebAssembly that can run on any platform that is supported within the Extism WASM ecosystem.

The key is the enhance-ssr.wasm bundle, a 4.1MB WebAssembly version of the enhance-ssr JavaScript library, compiled using the Extism JavaScript PDK (Plugin Development Kit) which itself bundles a WebAssembly version of QuickJS. # 8th April 2024, 7:44 pm

Bringing Python to Workers using Pyodide and WebAssembly (via) Cloudflare Workers is Cloudflare’s serverless hosting tool for deploying server-side functions to edge locations in their CDN.

They just released Python support, accompanied by an extremely thorough technical explanation of how they got that to work. The details are fascinating.

Workers runs on V8 isolates, and the new Python support was implemented using Pyodide (CPython compiled to WebAssembly) running inside V8.

Getting this to work performantly and ergonomically took a huge amount of work.

There are too many details in here to effectively summarize, but my favorite detail is this one:

“We scan the Worker’s code for import statements, execute them, and then take a snapshot of the Worker’s WebAssembly linear memory. Effectively, we perform the expensive work of importing packages at deploy time, rather than at runtime.” # 2nd April 2024, 4:09 pm

The Dropflow Playground (via) Dropflow is a “CSS layout engine” written in TypeScript and taking advantage of the HarfBuzz text shaping engine (used by Chrome, Android, Firefox and more) compiled to WebAssembly to implement glyph layout.

This linked demo is fascinating: on the left hand side you can edit HTML with inline styles, and the right hand side then updates live to show that content rendered by Dropflow in a canvas element.

Why would you want this? It lets you generate images and PDFs with excellent performance using your existing knowledge HTML and CSS. It’s also just really cool! # 22nd March 2024, 1:33 am

PGlite (via) PostgreSQL compiled for WebAssembly and turned into a very neat JavaScript library. Previous attempts at running PostgreSQL in WASM have worked by bundling a full Linux virtual machine—PGlite just bundles a compiled PostgreSQL itself, which brings the size down to an impressive 3.7MB gzipped. # 23rd February 2024, 3:56 pm

The original WWW proposal is a Word for Macintosh 4.0 file from 1990, can we open it? (via) In which John Graham-Cumming attempts to open the original WWW proposal by Tim Berners-Lee, a 68,608 bytes Microsoft Word for Macintosh 4.0 file.

Microsoft Word and Apple Pages fail. OpenOffice gets the text but not the formatting. LibreOffice gets the diagrams too, but the best results come from the Infinite Mac WebAssembly emulator. # 13th February 2024, 4:06 pm

urllib3 2.2.0. Highlighted feature: “urllib3 now works in the browser”—the core urllib3 library now includes code that can integrate with Pyodide, using the browser’s fetch() or XMLHttpRequest APIs to make HTTP requests (to CORS-enabled endpoints). # 30th January 2024, 4:31 pm

ColBERT query-passage scoring interpretability (via) Neat interactive visualization tool for understanding what the ColBERT embedding model does—this works by loading around 50MB of model files directly into your browser and running them with WebAssembly. # 28th January 2024, 4:49 pm

NYT Flash-based visualizations work again. The New York Times are using the open source Ruffle Flash emulator—built using Rust, compiled to WebAssembly—to get their old archived data visualization interactives working again. # 21st January 2024, 5:58 am

container2wasm (via) “Converts a container to WASM with emulation by Bochs (for x86_64 containers) and TinyEMU (for riscv64 containers)”—effectively letting you take a Docker container and turn it into a WebAssembly blob that can then run in any WebAssembly host environment, including the browser.

Run “c2w ubuntu:22.04 out.wasm” to output a WASM binary for the Ubuntu 22:04 container from Docker Hub, then “wasmtime out.wasm uname -a” to run a command.

Even better, check out the live browser demos linked fro the README, which let you do things like run a Python interpreter in a Docker container directly in your browser. # 3rd January 2024, 11:21 pm