WasmAssembly
WebAssembly (abbreviated Wasm, a contraction of “WebAssembly”, not an acronym, hence not using all-caps) is a safe, portable, low-level code format designed for efficient execution and compact representation. An assembly is a group of people gathered together in one place for a common purpose. In this show with the whimsical name WasmAssembly (get it?), Thomas Steiner, Developer Relations Engineer at Google, chats with experts from the community about the past, present, and future developments happening in the world of WebAssembly.
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WebAssembly from the Ground Up with Patrick Dubroy and Mariano Guerra
10/20/2025
WebAssembly from the Ground Up with Patrick Dubroy and Mariano Guerra
Get ready for WasmAssembly episode 16! Host Thomas Steiner sits down with Patrick Dubroy and Mariano Guerra, authors of the ebook "WebAssembly from the Ground Up." Discover how they're teaching Wasm by building a compiler in JavaScript, why writing WebAssembly by hand is crucial, and their thoughts on the future of compiler education. Tune in to learn about Ohm, the surprising omission of WAT, and what a potential part 2 of their book might cover! Chapters: 0:00 - Welcoming Patrick and Mariano, authors of "WebAssembly from the Ground Up 1:34 - How the book came to be 5:34 - How the co-authors met 9:13 - Who should learn WebAssembly by actually writing it? 13:13 - Is it time to retire the Dragon Book? 17:42 - What is Ohm, what it has to do with the programming language Wafer, and why they chose Ohm for the book 27:22 - Compiling Ohm grammars to Wasm 30:22 - The on-purpose omission of the Wasm text format WAT 38:27 - A potential part 2 of the book 43:36 - The biggest surprise when writing the book 50:42 - Wasm, but not Resources: Mariano Guerra on LinkedIn: Patrick Dubroy on LinkedIn: WebAssembly from the Ground Up: Learn WebAssembly: WebAssembly website Issue: Consider adding a pure Wasm tutorial: Let's Build a Compiler, by Jack Crenshaw: Simpletron Machine Language and Compiler from Deitel’s Java book: Little Riak Core Book: Failed PR "Initial tests for globals" to the Wasm spec: Short lived "WebAssembly Weekly" newsletter: The Dragon Book: Ohm: Human Advancement Research Community (HARC): Communications Design Group (CDG): Forth dialect implemented in C, JavaScript, WebAssembly and compiled from C to asm.js and WebAssembly: Minimal Object Oriented runtime in WAT and WasmGC: wasm-tools: Apple's Pascal "syntax" poster: Niklaus Wirth: Lilith Computer: Oberon System: Bill Hader on feedback: How Julia Evans asks for feedback: Patrick's blog post "Reflections on writing a book": Quarterback: Max Bernstein's blog: Thorsten Ball's newsletter: Gleam Programming Language: Sonic Pi: Future of Coding Newsletter: Patrick Dubroy on Bluesky: Patrick Dubroy on Mastodon: Mariano Guerra on Bluesky: Mariano Guerra on Mastodon: WebAssembly from the Ground Up ebook on Bluesky: WebAssembly from the Ground Up ebook on Mastodon:
/episode/index/show/wasmassembly/id/38646610
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CG, WG, W3C, Lively—Wasm standardization with Thomas Lively - WasmAssembly
09/29/2025
CG, WG, W3C, Lively—Wasm standardization with Thomas Lively - WasmAssembly
In this episode of WasmAssembly, host Thomas Steiner welcomes Thomas Lively from Google, the new co-chair of the W3C WebAssembly Community Group. Taking over the role from past guest Deepti Gandluri (episode #2), we seize the opportunity to ask Lively the exact same three questions we posed to Deepti—listen back to compare their perspectives! In the second half, the two Thomases dive deep into the proposals Lively is personally championing, covering Custom Descriptors and JS Interop, and the highly-anticipated Shared-Everything Threads. Chapters: 0:00 - The Wasm team "Thomas" confusion 0:57 - Thomas' way into Google's Wasm team 4:10 - Wasm CG vs. Wasm WG 9:39 - Is Wasm standardization moving slowly? 17:58 - Wasm at Google and the Chrome team 22:33 - The Custom Descriptors and JS Interop proposal 35:02 - The Shared-Everything Threads proposal 43:28 - Wasm, but not Resources: Thomas Lively on LinkedIn → WebAssembly Community Group → From asm.js to Wasm with Emscripten creator Alon Zakai → CG, WG, W3C, Deepti—Wasm standardization with Deepti Gandluri → Custom Descriptors and JS Interop → WebAssembly threads → Shared-Everything Threads → Thomas Lively on Bluesky →
/episode/index/show/wasmassembly/id/38393620
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Dart, Flutter, and WasmGC with Ömer Ağacan and Martin Kustermann
07/14/2025
Dart, Flutter, and WasmGC with Ömer Ağacan and Martin Kustermann
In this episode of WasmAssembly, your host Thomas Steiner is joined by Ömer Ağacan and Martin Kustermann from the Dart team at Google. They explore Dart, the language behind Flutter, and how Dart nearly landed in V8 alongside JavaScript, and why Flutter doubled down on Dart and WebAssembly Garbage Collection (WasmGC). Ömer and Martin then share insights on Dart’s performance leap from dart2js to dart2wasm, its potential beyond the browser, and what the WasmGC transition means for developers and the broader ecosystem. Finally, they look at Jaspr, Dart-only web apps, or how different browsers are handling WasmGC. This episode again is packed with sharp technical detail and bold visions for the future of WebAssembly. Resources: Dart → Flutter → Before Flutter | Rubber Duck Engineering | Episode #100 → State of Developer Ecosystem Report → What's new in Flutter → Dart & Flutter momentum at Google I/O 2025 → Accessibility in Flutter on the Web → Stateful hot reload in DartPad → WebAssembly (Wasm) compilation → Support for WebAssembly (Wasm) → WebAssembly Garbage Collection (WasmGC) now enabled by default in Chrome → Wasm-feature-detect library → A new way to bring garbage collected programming languages efficiently to WebAssembly → [dart2wasm] Support non-JS wasm runtimes → Safari bug: Umbrella: Using Canvas image sources between different canvases and canvas types is slow → Firefox bug: OffscreenCanvas.transferToImageBitmap incurs a copy → Ömer Ağacan on LinkedIn → Martin Kustermann on LinkedIn →
/episode/index/show/wasmassembly/id/37400120
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Enabling in-browser scientific computing with Wasm: David Kircos of Quadratic
04/28/2025
Enabling in-browser scientific computing with Wasm: David Kircos of Quadratic
On this WasmAssembly podcast episode, host Thomas Steiner speaks with David Kircos from Quadratic. They discuss how Quadratic's spreadsheet utilizes WebAssembly to enable scientific computing directly in the browser, leveraging tools like Pyodide, pandas, and numpy. The conversation also covers practical challenges such as bundling large-scale Wasm applications, exploring browser limitations, and Quadratic's integration of AI. Resources: David Kircos on LinkedIn → Building on the modern web app architecture → Pyodide → Pandas → Numpy → Esbuild-wasm → Using JavaScript in a spreadsheet → Making API requests from your spreadsheets → Quadratic Python roadmap: building a spreadsheet developers love → ES module integration proposal → AI spreadsheets are here: Quadratic + GPT → Database connectors → SQLite Wasm → Quadratic's GitHub organization →
/episode/index/show/wasmassembly/id/36339285
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Wasm on feature phones with Cloud Phone's Thomas Barrasso
03/24/2025
Wasm on feature phones with Cloud Phone's Thomas Barrasso
Feature phones? Yes, they still make them. And they run Wasm! In this WasmAssembly podcast, Thomas Steiner hosts Thomas Barrasso from CloudMosa to talk about the Cloud Phone platform and what it takes to run WebAssembly on tiny feature phones by streaming Web apps from a remote server that runs Chromium. Resources: Thomas Barrasso on LinkedIn → CloudMosa (Puffin) → Cloud Phone → Building web apps for Cloud Phone → Cloud Phone simulator → KaiOS → Puffin Cloud Isolation → Telegram client for KaiOS → Wasm implementation of algorithms used in Telegram → Stolen Focus book → Reach out → Thomas' email:
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WebGPU and wasi-gfx with renderlet
02/24/2025
WebGPU and wasi-gfx with renderlet
In this WasmAssembly podcast episode, Sean Isom and Mendy Berger from renderlet join host Thomas Steiner. Discover renderlet, a WebAssembly framework for writing graphics code that runs on any platform. Resources: Mendy Berger on LinkedIn → Sean Isom on LinkedIn → Renderlet → renderlet Wasm I/O talk → renderlet Wasm I/O slides → Drawing to canvas in Emscripten → Multi-draw indirect GPU feature → Mesh shaders → Work graphs → When in doubt, writeBuffer() → Fine grained control of memory proposal → Streams.wit → wasi-gfx talk: → wasi-gfx proposal → Web IDL → WIT → Webidl2wit → Mendy Berger on Mastodon → Sean Isom on X →
/episode/index/show/wasmassembly/id/35407495
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Protecting apps with Arcjet through WebAssembly
02/03/2025
Protecting apps with Arcjet through WebAssembly
WebAssembly is known for its speed and security, but can it be applied to enhance application security as a whole? Join Arcjet's CEO David Mytton and host Thomas Steiner on WasmAssembly as they delve into Arcjet’s innovative use of Wasm for crucial security functions like bot detection, rate limiting, and data redaction, providing developers with a powerful yet manageable security toolkit. Resources: Squishy Wasm apps using Extism with Dylibso's Steve Manuel - WasmAssembly → David Mytton's blog → Console Devtools podcast episode with Fermyon's Matt Butcher → Arcjet → Arcjet Wasm blog posts → Arcjet example app → @arcjet/next package → Arcjet JS SDK → Jco → jco example → Wasm-bindgen → Arcjet-js PR where we switched, with some comments on reasoning → Componentize-py → Componentize-dotnet → ComponentizeJS → Wasm Interface Type (WIT) → Extism →
/episode/index/show/wasmassembly/id/35127825
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Taking Fermyon's Spin for a spin with Thorsten Hans
01/10/2025
Taking Fermyon's Spin for a spin with Thorsten Hans
Join Thomas Steiner as he chats with Thorsten Hans, Senior Cloud Advocate at Fermyon, about the exciting world of WebAssembly serverless functions and microservices with the Spin framework. Discover how Spin uses WebAssembly for lightning-fast cold starts and great portability, and explore the advantages of building microservice applications with Spin's diverse language support. Thorsten and Thomas also delve into the role of WebAssembly standards in shaping the future of cloud-native development. Tune in for this insightful conversation on the cutting edge of WebAssembly technology! Resources: Thorsten Hans' Fermyon blog posts → Thorsten Hans on X → Thorsten Hans' blog → Thorsten Hans on LinkedIn → Thorsten Hans on joining Fermyon → Till Schneidereit on LinkedIn → Fermyon Spin → Introducing Spin → Fermyon Spin on GitHub → Building Spin Components in JavaScript → WasmAssembly episode "Squishy Wasm apps using Extism with Dylibso's Steve Manuel": → Spin JS/TS SDK → ComponentizeJS → WASI HTTP → SpiderMonkey → StarlingMonkey → Spin Rust SDK → Spin SQLite storage → Spin Serverless AI →
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Squishy Wasm apps using Extism with Dylibso's Steve Manuel - WasmAssembly
11/18/2024
Squishy Wasm apps using Extism with Dylibso's Steve Manuel - WasmAssembly
Join host Thomas Steiner and Steve Manuel from Dylibso as they dive deep into the world of "squishy" Wasm applications. Steve discusses Dylibso's mission to make all software squishy, using Wasm to unlock flexibility and extensibility in software development. The episode explores Dylibso's projects like Extism and Chicory, and how Extism is being used in production with Wasm today. Come for the Extism logo, and stay for Tom's provocative questions on Extism's role in the WebAssembly ecosystem. Resources: Steve Manuel on LinkedIn → Steve Manuel on X → Dylibso → XTP → Extism → Observe → Chicory → Some Extism integrators → Extism logo → Run an Extism plugin → Write an Extism plugin → Extism plugins without officially supported plugin development kit → WebAssembly Component Model → Wasm Interface Type (WIT) → WebAssembly System Interface (WASI) → Why Extism → Extism performance blog post → Beyond the HTTP API: WebAssembly and the Future of Systems Integration → Enhance Wasm → Alone (survival show) →
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A deep dive into WebAssembly with Thomas Nattestad - WasmAssembly
10/28/2024
A deep dive into WebAssembly with Thomas Nattestad - WasmAssembly
In this episode, WasmAssembly host, Thomas Steiner, chats with Thomas Nattestad, Product Manager on the Google Chrome team. Learn about Chrome's investment in WebAssembly, WebAssembly caching and if there's a solution for cross-origin caching, canvas-rendered apps, and Thomas' take on WebAssembly DOM access and whether WebAssembly will replace JavaScript. Finally, the two talk about the Wasm ES module integration and what this means for bundlers. Resources: Thomas' BlinkOn 9 talk → Thomas' SFHTML5 talk "What, Why, and How to WebAssembly?": (Sep 29, 2018) Thomas wishing for VB6 for Wasm: May 30, 2019) for Wasm: (Apr 13, 2019) WebAssembly at Google WasmCon talk: Flutter renderers → Qt for WebAssembly → Flutter support for WebAssembly → Kotlin Compose Multiplatform → Source phase imports proposal → WebAssembly ES module integration proposal → Angular ES module exploration →
/episode/index/show/wasmassembly/id/33642942
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Special episode on the June meeting of the WebAssembly Community Group - WasmAssembly
10/14/2024
Special episode on the June meeting of the WebAssembly Community Group - WasmAssembly
This is a special episode of the WasmAssembly podcast, recorded at the June face-to-face meeting of the WebAssembly community group that took place at the WebAssembly Research Center of the Carnegie Mellon University in Pittsburgh, Pennsylvania. Thomas Steiner was there for two days, day zero, a pre-event in the form of an academic research day, and day one of the actual face-to-face meeting. While there, he spoke with a lot of the attendees, and this episode will give you a bit of an impression of what was presented and discussed during the meeting. Resources: June meeting of the WebAssembly Community Group → Research day agenda → Elizabeth Gilbert → Flexible Non-intrusive Dynamic Instrumentation for WebAssembly → Adam Bratschi-Kaye → Internet Computer → WebAssembly and the Internet Computer Protocol → Dan Gohman → The World of WASI → Ben Titzer → WebAssembly Research Center → Adam Klein → Yuri Iozzelli → Branch hinting → Emanuel Ziegler → Compilation hints → Ilya Rezvov → Half-precision (FP16) → Ben Visness → Memory control → Thomas Lively → Day 1 agenda →
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Exploring the Bytecode Alliance with Cosmonic's Bailey Hayes - WasmAssembly
09/30/2024
Exploring the Bytecode Alliance with Cosmonic's Bailey Hayes - WasmAssembly
In this episode, your host Thomas Steiner chats with Cosmonic's CTO and Bytecode Alliance technical steering committee and board member, Bailey Hayes, about the exciting world of WebAssembly at her company, and specifically at the Bytecode Alliance. After exploring how Cosmonic makes use of WASI for their wasmCloud product, they get into details about the Bytecode Alliance, the workstreams and projects hosted there, and how to work with it. Resources: Bailey Hayes on LinkedIn → Cosmonic's post welcoming Bailey → WebAssembly on the factory floor → What is Cosmonic → jco → jco example → SpiderMonkey → WASI http → WasmAssembly episode with Ryan Hunt on string built-ins: The various HTTP methods in WASI http → WasmAssembly episode with Luke Wagner on WASI and the component model → Bytecode Alliance → WasmEdge runtime → Bytecode Alliance board → Bytecode Alliance technical steering committee → Bytecode Alliance community stream update → Bytecode Alliance updated developer roadmap → Bytecode Alliance projects → Wasmtime → Cranelift → WAMR → Javy → WebAssembly System Interface (WASI) → Component model → WASI Subgroup in the WebAssembly CG → Brandon Sanderson's Mistborn saga → Bailey on Mastodon → Bailey on X → Bailey's Bytecode Alliance videos →
/episode/index/show/wasmassembly/id/33207552
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A promising feature: JavaScript Promise Integration with Francis McCabe - WasmAssembly
08/26/2024
A promising feature: JavaScript Promise Integration with Francis McCabe - WasmAssembly
In this episode, Thomas Steiner chats with Francis McCabe from Google, who's the champion of the JavaScript Promise Integration and the Stack Switching proposals. They go from talking about synchronous assumptions in code over to discussing the JavaScript Promise Integration (JSPI) proposal and how to use it in practice, its performance implications, and how to use it in practice. After exploring a neat side effect of JSPI, namely lazy loading, the fall into the rabbit hole of comparing JSPI to the upcoming ES module integration of Wasm. Finally, Francis gives an overview of his other early stage Stack Switching proposal. Resources: The Paper introducing Go! → The JSPI proposal → JSPI entering origin trial → JSPI origin trial → Introducing JSPI → The new JSPI API → The JSPI API change → Code example → Stack-Switching Proposal for WebAssembly → The Vivant series →
/episode/index/show/wasmassembly/id/32663277
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String built-ins with Mozilla's Ryan Hunt - WasmAssembly
08/05/2024
String built-ins with Mozilla's Ryan Hunt - WasmAssembly
In this episode, Thomas Steiner interviews Mozilla's Ryan Hunt, who's the champion of the string built-ins proposal. They first discuss Ryan's way into Mozilla and his role in the SpiderMonkey team, and then dive deep into the string built-ins proposal and some challenges and rabbit holes with it. Resources: Ryan Hunt on LinkedIn → SpiderMonkey blog → WasmGC proposal → Google Sheets WasmGC → BrowserTech podcast episode with Row Zero → String Built-ins proposal → Potential other built-ins → Lin Clark's post on calls between JavaScript and WebAssembly being finally fast → The problems with `this` and operators like `===` → Using built-ins → Polyfilling built-ins → Scheme Wasm compiler → OCaml compiler → Compact impact section proposal → Compact impact section slides → Memory64 proposal → Seinfeld → Frasier → Scrubs → Culver's restaurants → Menards home improvement store → Ryan on GitHub →
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The WASI Revolution: Luke Wagner on WebAssembly's Past, Present, and Future - WasmAssembly
06/24/2024
The WASI Revolution: Luke Wagner on WebAssembly's Past, Present, and Future - WasmAssembly
In this episode, Thomas Steiner interviews Luke Wagner, who works at Fastly. You’ll hear them chat about Luke’s time at Mozilla, how he remembers the Wasm launch, the WebAssembly System Interface (WASI) and the component model, his thoughts on where WebAssembly’s future lies, and much more. Resources: Luke Wagner's Wasm announcement blog post for Mozilla → The Wasm polyfill prototype → The PLDI 2017 paper → A WebAssembly milestone → V8's Wasm announcement → Edge's Wasm announcement → The WebAssembly browser preview → The magic number and the version field → The WebAssembly post-MVP future blog pos → WebAssembly performance patterns →https://goo.gle/4ce8qwE API Concerns with Structured Clone for Wasm Modules → Formal description of serializing and deserializing a Module → Don't allow IndexedDB serialization of WebAssembly.Module → Normative: Support [Serializable] for WebAssembly.Module → Cache support → WebAssembly developers → WebAssembly — Caching to HTML5 IndexedDB → The Lucet → The Lucet and Wasmtime teams join forces → Fastly hires entire Wasmtime team from Mozilla → What is WebAssembly? → Lucet Takes WebAssembly Beyond the Browser → Wasmtime—A fast and secure runtime for WebAssembly → How Lucet and Wasmtime make a stronger compiler, together → WASI 0.2: Unlocking WebAssembly’s Promise Outside the Browser → WASI 0.2 Launched → WebAssembly System Interface → WASI proposals → WASI HTTP → The wit format → What color is your function? → A stream of consciousness on the future of async in the Component Model → Revolutions podcast → Luke Wagner on GitHub → Luke Wagner on X → #WebAssembly #Wasm #WASI Speaker: Thomas Steiner
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CG, WG, W3C, Deepti—Wasm standardization with Deepti Gandluri - WasmAssembly
05/23/2024
CG, WG, W3C, Deepti—Wasm standardization with Deepti Gandluri - WasmAssembly
In this episode, Tom interviews Deepti Gandluri, the Chair of the WebAssembly Community Group at the W3C. You will hear about the difference between the W3C WebAssembly Community Group and Working Group, how Wasm is standardized, how Deepti got into WebAssembly, and the challenges the WebAssembly team at Google faces being part of the Chrome team. Deepti also discusses her favorite Wasm features, how the Community Group might react to a browser-specific proposal, how WASI might work given browser security constraints, and new Wasm features she's excited about in the context of AI. Resources: Episode 1 with Alon Zakai → Deepti, Chair of the Community Group: → Deepti, member of the Working Group → WebAssembly Summit opening keynote → WebAssembly Community Group → WebAssembly Working Group → WebAssembly W3C Process GitHub → TC39 process document → File System Access API → Web Serial API → V8 Wasm source code in Chromium → WebAssembly active proposals → WebAssembly inactive proposals → Wasm feature detection proposal → JavaScript promise integration proposal → JavaScript promise integration origin trial proposal → WasmGC proposal → WasmGC → WASI file system → Stringref proposal → Built-in Strings proposal → Deepti's Google I/O talk → Relaxed SIMD proposal → Half precision (FP16) proposal → Memory64 proposal →
/episode/index/show/wasmassembly/id/31419022
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From asm.js to Wasm with Emscripten creator Alon Zakai - WasmAssembly
04/25/2024
From asm.js to Wasm with Emscripten creator Alon Zakai - WasmAssembly
Learn about some early WebAssembly history from one of the co-creators of Wasm, Alon Zakai! Follow along how Alon explains how we came from Native Client to asm.js and then finally to WebAssembly, and explore some interesting historical and present day sidetracks on the way. Resources: Alon Zakai: Homepage → (has links to all the social profiles, too) LinkedIn profile → Native Client (NaCl) → Portable NaCl (PNaCL) → Compiling LLVM to JavaScript → BananaBread demo → asm.js → asm.js presentation → asm.js blog posts → Emscripten and WebAssembly presentation → Bringing the Web up to speed with WebAssembly paper → Polywasm → Qt apps compiled to → Quake 3 Arena compiled to WebAssembly →
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