Data Across the Wasm Boundary By Dan Phillips

Many people are excited about WebAssembly. However, as with any budding ecosystem, one can encounter roadblocks when trying to do seemingly simple things. This is especially true in the server-side Wasm space, where tooling is under active development as current approaches evolve. An early head-scratcher for many, even after compiling a first Wasm module is “…but how do I get data in, and out, of a WebAssembly module?” Once you peek behind the curtain, you’ll find there are many options for this – wasm-bindgen, wit-bindgen, polyglot, gRPC, JSON, and more – though you may be confused as to why there is so much variety. You may also notice what appear to be limitations: Wasm primitives being only numbers, single returns, etc. Finally, what about WASI, the WebAssembly System Interface? How easy is it to get data with a network connection? From a file on the host? This talk will cover all of these available options, the strengths, similarities, differences and – most importantly – their usage, so that you will have a confident understanding of the landscape when you begin your next WebAssembly project. DAN PHILLIPS Daniel Phillips is a Senior Engineer at Loophole Labs, where one of his main areas of focus is server-side WebAssembly. He is also the founder and organizer of the WebAssembly Chicago group.