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World Congress 2026 Europe • Jul 9, 2026 • Session details

From Bytes to Execution: Writing a WebAssembly Runtime in Rust

Gaurav Gahlot

How does WebAssembly actually execute code under the hood? Strip a WASM engine down to its absolute essentials and build a minimal, stack-based runtime completely in Rust.

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#1 about 2 min

Speaker background and open source Kubernetes edge computing projects

Understanding previous open source project experience reveals context around cloud-native perspectives and dynamic resource allocation tooling.

#2 about 4 min

Core concepts of WebAssembly portability and sandboxed execution

Achieving highly scalable cross-platform behavior requires understanding how WebAssembly acts as a portable bytecode with built-in closed sandboxing.

#3 about 3 min

Comparing WebAssembly text representation and binary module structure

Examining text representations clarifies how compiled WebAssembly programs decompose into foundational headers and uniquely formatted functional element sections.

#4 about 2 min

Runtime execution stages and the minimal Whisk interpreter

Stripping software VM engines down reveals how pure WebAssembly execution operates via decoding, validation, instantiation, and interpretation phases.

#5 about 3 min

Parsing WebAssembly binary headers and mapping module sections

Analyzing standard binary byte prefixes directly exposes the fundamental architectural building blocks of a module format and memory payloads.

#6 about 3 min

Validating memory safety and type constraints in WebAssembly modules

Validating internal code layouts against expected function signatures actively guarantees reliable memory isolation during upcoming runtime executions.

#7 about 3 min

Resolving external inputs and linear memory instantiation processes

Because modules lack direct hardware access out of the box, they must request critical memory array allocations from host systems.

#8 about 4 min

Executing instructions using a stack machine model in Rust

Building a functional runtime mechanism requires carefully handling instruction logic by pushing and popping sequence formats mapped through language enums.

#9 about 2 min

Improving runtime performance through just-in-time compilation

Optimizing base VM runtime sluggishness incorporates processing modules instantly using active just-in-time translation representations.

#10 about 3 min

Standardizing host interactions using WASI and cloud-native frameworks

Overcoming inherent ecosystem isolation safely involves relying on standard system interfaces to govern necessary external hardware operating bounds securely.

#11 about 1 min

Demonstrating compiled WebAssembly binary sizes via terminal output

Contrasting resulting compiled executable overhead inherently emphasizes slightly how lightweight WebAssembly functional routines scale efficiently on server environments.

Matching moments

2:31 min

Compiling Rust code to WebAssembly for JavaScript runtimes

Edo Edo · WWC 2024

1:57 min

Compiling Rust to WebAssembly for browser deployment

Edoardo Dusi · LIVE

2:40 min

Core concepts and execution mechanics of WebAssembly modules

Edo Edo · WWC 2024

4:02 min

Compilers and runtimes in the WebAssembly ecosystem

Edoardo Dusi · LIVE

2:27 min

Introduction to WebAssembly in a cloud computing context

Edo Edo · WWC 2024

4:54 min

The origins and design principles of WebAssembly

Maurice Brinkmann · WWC 2023

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