WASM 3.0 with Andreas Rossberg

Andreas Rossberg unpacks WASM 3.0, covering new capabilities like garbage collection, exception handling, tail calls, and support for 64-bit addressing with multiple memories. The discussion explores deterministic profiles following relaxed sim, WebAssembly’s capability-based security model, and advances in sandboxing and module design. Andreas connects these features to practical use cases in JavaScript engines and applications like Google Sheets, then looks ahead to experimental work on threading, stack switching, and async programming models shaping the next phase of the WebAssembly ecosystem. Links Website: https://people.mpi-sws.org/~rossberg GitHub: https://github.com/rossberg Resources WASM 3.0 Completed: https://webassembly.org/news/2025-09-17-wasm-3.0 Chapters 00:00 Intro – Andreas Rossberg and the WebAssembly 3.0 Update 01:05 The State of WebAssembly Today 02:15 Why WebAssembly Exists Beyond the Web 03:20 From WebAssembly 2.0 to 3.0 – What’s Actually New 04:30 Garbage Collection: A Game-Changer for Managed Languages 06:00 The Vision of WebAssembly as a Universal Compilation Target 07:40 How GC Support Unlocks Java, Kotlin, and Dart on WASM 09:10 Expanding to 64-bit Memory – Performance and Limits 10:40 WebAssembly for Databases, AI, and LLMs 12:00 Sandboxing and Security by Design 13:10 How Capabilities and Static Analysis Keep WASM Safe 14:30 Multi-Memory Support and Real-World Use Cases 16:00 Developer Ergonomics vs. Specification Purity 17:20 Tail Calls and Functional Programming Benefits 18:40 Function Tables and Secure Indirection 20:00 Exception Handling Finally Arrives 21:10 Determinism, Efficiency, and Why It Matters for Blockchain 22:30 SIMD and Hardware Divergence Across Platforms 24:00 Balancing Portability with Performance 25:20 The Design Philosophy Behind WebAssembly 26:30 Why WASM Rejects Language-Specific Features 27:40 Proposal Process: Who Decides What Gets In 29:00 Browser Vendors and Implementation Challenges 30:10 Early Deployments: GC, Tooling, and Adoption Stories 31:30 Threads, Stack Switching, and the Future of Concurrency 33:00 Async/Await and Coroutines on WebAssembly 34:30 What’s Coming Next for WASM Developers 35:40 How to Get Involved – Working Groups and Proposals 37:00 Closing Thoughts and Thanks We want to hear from you! How did you find us? Did you see us on Twitter? In a newsletter? Or maybe we were recommended by a friend? Fill out our listener survey (https://t.co/oKVAEXipxu)! https://t.co/oKVAEXipxu Let us know by sending an email to our producer, Elizabeth, at elizabet.becz@logrocket.com (mailto:elizabeth.becz@logrocket.com), or tweet at us at PodRocketPod (https://twitter.com/PodRocketpod). Follow us. Get free stickers. Follow us on Apple Podcasts, fill out this form (https://podrocket.logrocket.com/get-podrocket-stickers), and we’ll send you free PodRocket stickers! What does LogRocket do? LogRocket provides AI-first session replay and analytics that surfaces the UX and technical issues impacting user experiences. Start understanding where your users are struggling by trying it for free at LogRocket.com. Try LogRocket for free today. (https://logrocket.com/signup/?pdr)