Detect WebAssembly
WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications.
Detection looks at response headers, script sources, javascript globals across 4 fingerprint rules among the site's public responses.
01
Websites using WebAssembly
Loading website list…
02
Signal classes
PluginView evaluates public page signals in these classes when identifying WebAssembly. Individual fingerprint rule bodies are proprietary and are not published.
- Response headers
- Script sources
- JavaScript globals
03
Example public indicators for WebAssembly
Illustrative indicators derived from public catalog metadata for WebAssembly. A live scan may match additional proprietary rules beyond these examples.
- content-type: application/wasm
- wasm_exec.js
- wasmBinary
- wasmBinaryFile
04
What a detection means
- Establishes
- One or more public signals on the scanned page matched a known WebAssembly signature (4 rules) at the time of the scan.
- Does not establish
- A sitewide install of WebAssembly, an active vendor contract, exclusive use, or that WebAssembly is still in place today.
05
How to check a site for WebAssembly
- 1. Enter the website URL in the scan form — homepage, pricing, checkout, or login pages usually expose the strongest WebAssembly signals.
- 2. PluginView reads only public responses (response headers, script sources, javascript globals) and scores them against the WebAssembly signature set (4 rules).
- 3. Review the confidence score and text explanation for WebAssembly on the results page.
06
FAQ: detecting WebAssembly
- Can PluginView detect WebAssembly without logging in?
- Yes. PluginView only reads publicly accessible responses when checking for WebAssembly — typically response headers, script sources, javascript globals. It does not bypass authentication or paywalls.
- What category is WebAssembly?
- WebAssembly is classified under Programming languages in the PluginView directory.
- How many fingerprint rules cover WebAssembly?
- This reference currently tracks 4 fingerprint rules across response headers, script sources, javascript globals. Individual rule bodies are proprietary and are not published.
- What public signals suggest a site uses WebAssembly?
- Illustrative public indicators for WebAssembly include content-type: application/wasm; wasm_exec.js; wasmBinary. A live scan may match additional proprietary rules beyond these examples.
