---
title: "Four Approaches to Debugging Server-side WebAssembly"
description: "Server-side WebAssembly offers Shopify Functions low cold-start latency and robust security, but debugging remains difficult because step-debugger support is less refined. The post compares four approaches: compiling to a native architecture, using LLDB or GDB with Wasmtime, using a dedicated WebAssembly debugger, and using browser developer tools. Native debugging generally provides the best variable rendering and a familiar workflow, though it may require stubs for external calls and cannot reproduce WebAssembly-specific behavior. Wasmtime keeps execution closer to the target environment, while dedicated and browser-based tools offer WebAssembly-specific capabilities but have missing features or lower-fidelity variable views. The recommended choice depends on whether the issue reproduces natively, and browser-based tooling may become more accessible as it improves."
---

# Four Approaches to Debugging Server-side WebAssembly

[Shopify](https://yomu.fyi/company/shopify) · 2023-10-18 · Sep 7, 2022

**Type:** Explainer

## Summary

Server-side WebAssembly offers Shopify Functions low cold-start latency and robust security, but debugging remains difficult because step-debugger support is less refined. The post compares four approaches: compiling to a native architecture, using LLDB or GDB with Wasmtime, using a dedicated WebAssembly debugger, and using browser developer tools. Native debugging generally provides the best variable rendering and a familiar workflow, though it may require stubs for external calls and cannot reproduce WebAssembly-specific behavior. Wasmtime keeps execution closer to the target environment, while dedicated and browser-based tools offer WebAssembly-specific capabilities but have missing features or lower-fidelity variable views. The recommended choice depends on whether the issue reproduces natively, and browser-based tooling may become more accessible as it improves.

## Context

Debugging server-side WebAssembly introduces challenges that are common to other WebAssembly uses, including a less refined developer experience with step debuggers. The appropriate strategy depends on whether the problem can be reproduced in a native environment or occurs only when code runs in a WebAssembly engine.

## Approach / What changed

The post evaluates native compilation with a language-appropriate debugger, LLDB or GDB running WebAssembly through Wasmtime, dedicated WebAssembly debuggers such as Wasminspect, and browser-based debugging using Chrome DevTools support or converted source maps. It compares their variable rendering, feature support, setup requirements, and ability to reproduce WebAssembly-specific behavior.

## Takeaways

- Compiling to a native architecture usually provides the most usable variable rendering and familiar debugging workflow, but external WebAssembly calls may need to be stubbed or replaced.
- LLDB with Wasmtime can diagnose behavior that only appears in a WebAssembly environment and supports WebAssembly features unavailable to browsers or WebAssembly-specific debuggers.
- Dedicated and browser-based debuggers provide WebAssembly-oriented capabilities such as linear-memory inspection, but may lack mature features or make local variables unavailable.

**Tags:** [Architecture](https://yomu.fyi/topic/architecture), [Developer Experience](https://yomu.fyi/topic/developer-experience)

- Source: [Shopify](https://shopify.engineering/debugging-server-side-webassembly)
- Source URL: https://shopify.engineering/debugging-server-side-webassembly
- Ingested by Yomu: 2026-08-30T13:39:13.998Z

[Read original post](https://shopify.engineering/debugging-server-side-webassembly)