Compile Rust, C++, or Go to WebAssembly and run it in the browser, Node.js, and serverless runtimes: wasm-bindgen JS interop, WASI for system access, the Component Model, and SIMD.
Open the source and read safety notes before installing.
Source-backed facts for citing this resource, derived directly from the registry — also available as plain text for AI assistants.
Decision playbook
Signals are comparatively strong, but you should still validate source, privacy posture, and package provenance for your environment.
0
96
—
No baseline selected
No major trust-signal divergence detected in the current selection.
Confirm ownership and provenance before trusting install instructions.
Source link availableRequired
Open the canonical repository and verify ownership.
Source provenance statusRequired
Marked as first-party.
Metadata reviewed
Registry metadata indicates a reviewed listing.
Validate risk disclosures before installation or API wiring.
Safety notes presentRequired
Review the listed safety guidance before running commands.
Privacy notes presentRequired
Review data handling notes before connecting accounts or secrets.
Trust level risk gateRequired
Trust level does not block evaluation.
Check package metadata and artifact integrity signals.
Install payload available
Install or copy payload is available for review.
Package verification flag
Package marked verified.
Checksum metadata
SHA-256 hash is present.
Use compare context to validate trade-offs before adoption.
Compare tray has multiple entries
Add at least one more entry to compare trust differences.
Baseline comparison available
No baseline peer selected yet.
Diverging trust signals identified
No major trust-signal divergence found.
Setup at a glance
Copy-ready — paste the snippet to get started.
Adoption plan
Current risk score 0/100. Use staged verification before broader rollout.
Validate source and review signals before any execution.
Confirm source provenanceRequired
Source URL/provenance metadata is present.
Confirm metadata review state
Listing has review metadata.
Verify install payload
Install/config payload exists and can be inspected.
Confirm safety, privacy, and package integrity signals.
Review safety notesRequired
Safety notes are present.
Review privacy notesRequired
Privacy notes are present.
Verify package integrity metadata
Package verification/checksum metadata is available.
Adopt in controlled steps based on the selected plan.
Run in isolated sandbox firstRequired
Use a constrained sandbox and observe behavior across multiple tasks.
Roll out graduallyRequired
Roll out to a small cohort before wider usage.
Set monitoring and fallback
Define rollback path and monitor errors after adoption.
Evidence readiness
Required evidence gates are covered (6/6 signals complete).
Source repository/provenance is listed.
Required in this preset
Review metadata is present.
Required in this preset
Safety notes are present.
Required in this preset
Privacy notes are present.
Optional in this preset
Package integrity metadata is present.
Optional in this preset
Install payload is available.
Required in this preset
Required evidence gates are covered for this preset.
Decision timeline
6/6 steps complete with no blocking gaps for this preset.
triage
Source/provenance metadata is available.
triage
Review metadata is available.
verify
Safety notes are available.
verify
Privacy notes are available.
verify
Package integrity metadata is available.
rollout
Install payload is available.
No required blockers for this timeline preset.
Prerequisite readiness
6 prerequisites to line up before setup.
Safety & privacy surface
2 safety and 1 privacy notes across 2 risk areas. Review closely: permissions & scopes, network access.
| Platform | Support | Install path |
|---|---|---|
| claude-code | Native | .claude/skills/<skill-name>/SKILL.md |
| codex | Native | .agents/skills/<skill-name>/SKILL.md |
| windsurf | Native | .windsurf/skills/<skill-name>/SKILL.md |
| gemini | Native | .gemini/skills/<skill-name>/SKILL.md or .agents/skills/<skill-name>/SKILL.md |
| cursor | Adapter | .cursor/rules/<skill-name>.mdc |
| cli | Manual | AGENTS.md or tool-specific context file |
use wasm_bindgen::prelude::*;
#[wasm_bindgen]
pub fn fibonacci(n: u32) -> u64 {
match n {
0 => 0,
1 => 1,
_ => {
let mut a = 0u64;
let mut b = 1u64;
for _ in 2..=n {
let temp = a + b;
a = b;
b = temp;
}
b
}
}
}
#[wasm_bindgen]
pub struct Calculator {
cache: Vec<u64>,
}
#[wasm_bindgen]
impl Calculator {
#[wasm_bindgen(constructor)]
pub fn new() -> Calculator {
Calculator { cache: vec![0, 1] }
}
pub fn nth(&mut self, n: usize) -> u64 {
while self.cache.len() <= n {
let len = self.cache.len();
let next = self.cache[len - 1] + self.cache[len - 2];
self.cache.push(next);
}
self.cache[n]
}
}Build high-performance WebAssembly modules with WASI 0.3, multi-language support, and production-ready deployments for web, serverless, and AI workloads. WebAssembly (WASM) runs at near-native speeds across web browsers, serverless platforms, and edge computing environments. WASI Preview 3 adds async support and the Component Model improves interoperability, making WASM a strong fit for AI workloads, cloud-native services, and high-performance web apps. Features include Rust/C++/Go compilation to WASM, wasm-bindgen for JavaScript integration, WASI for system calls, Component Model for interoperability, binary size optimization, SIMD support for performance, and multi-runtime compatibility (browser, Node.js, serverless).
Claude can build production-ready WebAssembly modules that run at near-native speeds across web browsers, serverless platforms, and edge computing environments. WASI Preview 3 adds async support and the Component Model improves interoperability, making WASM a strong fit for AI workloads, cloud-native services, and high-performance web apps.
SKILL.md.SKILL.md content as reusable workflow instructions..gemini/skills/<skill-name>/SKILL.md or .agents/skills/<skill-name>/SKILL.md where supported..cursor/rules/*.mdc adapter for project rules.Required:
What Claude handles automatically:
Prompt: "Build a WebAssembly module in Rust that calculates Fibonacci numbers. Include JavaScript bindings and deploy to npm."
Claude will:
Prompt: "Create a WebAssembly module that applies image filters (grayscale, blur, sharpen) to ImageData from canvas. Optimize for processing 4K images in real-time."
Claude will:
Prompt: "Build a WebAssembly module that runs ONNX neural network models in the browser. Support image classification with MobileNetV3."
Claude will:
Prompt: "Create a WebAssembly module with WASI 0.3 that processes CSV files, performs data transformations, and writes results to stdout. Deploy to Fermyon Spin."
Claude will:
Choose Rust for Production: While multiple languages compile to WASM, Rust offers the best tooling (wasm-pack, wasm-bindgen) and smallest binary sizes. Ask Claude to use Rust unless you have specific requirements.
Optimize Binary Size: WASM modules should be <500KB for web deployments. Request wasm-opt -Oz optimization and enable LTO (Link-Time Optimization) in Cargo.toml.
Use Component Model: For WASI 0.3, request Component Model implementation for better interoperability and async support.
Memory Management: WebAssembly uses linear memory. Ask Claude to implement proper memory allocation strategies and avoid memory leaks with proper drop implementations.
JavaScript Interop: Use wasm-bindgen for seamless JavaScript integration. Request TypeScript definitions generation for better DX.
SIMD When Available: For compute-intensive tasks, ask Claude to use WebAssembly SIMD instructions for compute-intensive tasks.
"Create a WebAssembly module for my React app that:
1. Parses and validates 10MB JSON files instantly
2. Performs complex data aggregations
3. Exports results to CSV format
4. Includes TypeScript types
5. Loads asynchronously without blocking UI
6. Caches compiled module in IndexedDB
7. Falls back to JavaScript if WASM not supported"
"Build a WebAssembly SHA-256 hasher in Rust:
1. Implements Bitcoin mining algorithm
2. Uses multi-threading with Web Workers
3. Achieves >1000 hashes per second
4. Includes difficulty adjustment
5. Reports progress to JavaScript
6. Optimized with SIMD instructions"
"Create a WebAssembly H.264 decoder:
1. Decode video streams in real-time (30fps)
2. Output to canvas via ImageData
3. Support seeking and playback controls
4. Use multi-threading for parallel decode
5. Implement memory-efficient frame buffer
6. Package as Web Component"
"Build a WebAssembly SQLite query engine:
1. Compile SQLite to WASM with WASI
2. Implement virtual file system in browser
3. Support full SQL query syntax
4. Persist database to IndexedDB
5. Include transaction support
6. Expose async API to JavaScript
7. Add query performance analytics"
Issue: WASM module binary is too large (>2MB) Solution: Enable LTO and opt-level in Cargo.toml, run wasm-opt with -Oz flag, remove unused dependencies, and consider dynamic linking for shared code.
Issue: JavaScript can't call WASM functions Solution: Ensure wasm-bindgen attributes are present (#[wasm_bindgen]), rebuild with wasm-pack, and check that JavaScript imports the generated bindings correctly.
Issue: Performance slower than expected Solution: Enable WASM SIMD, use multi-threading with Web Workers, avoid frequent boundary crossings between JS and WASM, and profile with Chrome DevTools Performance tab.
Issue: Memory errors or crashes Solution: Check for buffer overflows, ensure proper memory allocation, implement Drop trait for cleanup, and use wasm-bindgen's #[wasm_bindgen(inspectable)] for debugging.
Issue: WASI functions not available Solution: Update to WASI SDK 0.3+, configure WASI runtime (wasmtime, wasmer), and use preview2 modules. Not all WASI functions are available in browser environments.
Issue: Cannot debug WASM code Solution: Enable source maps with wasm-pack build --dev, use Chrome DevTools WASM debugging, add console.log bindings via web_sys crate, or use wasmtime with --invoke for CLI debugging.
Show that WebAssembly WASM Module Development Skill is listed on HeyClaude. Paste this Markdown into your README — it renders the badge and links back to this page.
[](https://heyclau.de/entry/skills/webassembly-module-development)WebAssembly WASM Module Development Skill side by side with 3 alternatives on trust, install, platform support, and disclosed safety notes — all from reviewed registry metadata.
3 trust signals differ across this comparison (Package trust, Source provenance, Submitter).
Next steps differ across entries — use the actions in the table below to copy install commands and source links per resource.
| Field | Compile Rust, C++, or Go to WebAssembly and run it in the browser, Node.js, and serverless runtimes: wasm-bindgen JS interop, WASI for system access, the Component Model, and SIMD. Open dossier | Explore and script against REST APIs with comprehensive authentication support (API keys, OAuth 2.0, JWT Bearer tokens, Basic Auth), pagination utilities (cursor-based, offset-based, page-based), retry logic with exponential backoff and jitter, error handling for HTTP status codes, rate limiting with Retry-After hea... Open dossier | Build JavaScript and TypeScript apps with Bun, an all-in-one toolchain that replaces Node.js, npm, a bundler, and a test runner with one fast binary that executes TypeScript directly. Open dossier | Expert plugin marketplace authoring capability pack applying documented marketplace.json catalogs, /plugin marketplace add flows, private repo distribution, and supply-chain review from official plugin marketplace documentation. Open dossier |
|---|---|---|---|---|
| Next stepsDiffers | ||||
| Trust | ||||
| Review status | ReviewedMaintainer reviewed | ReviewedMaintainer reviewed | ReviewedMaintainer reviewed | ReviewedMaintainer reviewed |
| Package trustDiffers | Package verified2025-10-16 | Package verified2025-10-15 | Package verified2025-10-23 | Package not verified |
| Source provenanceDiffers | Source-backed | No submission link | No submission link | Submission linkedSource submission |
| SubmitterDiffers | — | — | — | kiannidev |
| Install risk | Review first | Low risk | Low risk | Review first |
| Notes | Safety ✓ Privacy ✓ | Safety ✓ Privacy ✓ | Safety ✓ Privacy ✓ | Safety ✓ Privacy ✓ |
| Brand | — | — | — | — |
| Category | skills | skills | skills | skills |
| Source | First-party | First-party | First-party | Source-backed |
| Author | JSONbored | JSONbored | JSONbored | kiannidev |
| Added | 2025-10-16 | 2025-10-15 | 2025-10-23 | 2026-06-16 |
| Platforms | ||||
| Harness | ||||
| Source repo | — | — | — | — |
| Safety notes | ✓The install step downloads and unzips a package, and building modules runs compiler toolchains (wasm-pack, Emscripten, or the WASI SDK); run them in a trusted project directory and review generated build files. WASI grants modules system access (files, env, sockets); grant only the capabilities a module needs and review WASI imports before running untrusted modules. | ✓Setup downloads/unzips a package, and the harness makes live HTTP requests (including POST/PUT/DELETE) to the APIs you point it at; review endpoints and methods before running against production services. | ✓Installing Bun globally (`npm install -g bun`) adds a runtime to your system; install from the official npm package or bun.sh and keep it updated. Bun runs JavaScript/TypeScript with full system access like Node.js; review code before executing it, especially untrusted scripts. | ✓Autonomous runs can execute tools without mid-run user input—scope paths and connectors first. Do not enable destructive automation without explicit approval gates. Review outputs as draft until a human validates evidence. |
| Privacy notes | ✓Compiling and running modules is local, but a module that fetches remote models or data (for example ONNX inference) sends and receives data over the network; review what it downloads and where results go. | ✓API requests carry credentials (API keys, OAuth/JWT tokens) and request/response bodies; keep secrets in environment variables, and review what data is sent to and logged from third-party APIs. | ✓Bun apps you build can read local files, environment variables, and make network calls like any Node.js app; keep secrets in environment variables and review what your code sends externally. | ✓Run output may contain proprietary code and credentials. Summaries for external channels require redaction. |
| Prerequisites |
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| Install | | | | — |
| Config | — | — | — | — |
| Citations | ||||
| Claim | Unclaimed | Unclaimed | Unclaimed | Unclaimed |
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