Don't Trust Anything! Real-world Uses For WebAssembly
summary
Demonstrates running untrusted code safely by compiling it to WebAssembly, using WASI to grant only specific IO, limiting memory and instruction “fuel,” and executing many sandboxes in-process with Wasmtime and other engines. Shows a live rock‑paper‑scissors site where Python interpreters and AssemblyScript bots run as WASM binaries, VMs take ~100s ms to start while Cloudflare V8 isolates hit ~5 ms and Wasmtime/Fastly cite microseconds, and Shopify and Firefox already use WASM sandboxes in production.
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chapters (14)
- 0:00Intro
- 0:25Untrusted code
- 14:23WebAssembly
- 19:17Sandboxing without using a separate process
- 24:10WASI (WebAssembly System Interface)
- 29:48Demo
- 34:03WASI continued
- 34:50Case study: Shopify functions
- 36:41Case study: Mozilla Firefox
- 39:28Security
- 41:49Reminder: Security in depth
- 42:39Where are we now?
- 45:50When are you running untrusted code?
- 47:54Outro
