[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"extension:v3:en:wasm":3},{"resolvedFromAlias":4,"canonicalExt":5,"ext":5,"name":6,"category":7,"categoryName":8,"updatedAt":9,"popularity":10,"summary":11,"howToOs":12,"quickAnswer":18,"answerIntro":19,"whatIs":20,"description":21,"furtherReading":22,"openInstructions":41,"commonIssues":58,"securityNotes":80,"faq":84,"aliases":97,"mimeTypes":98,"relatedExtensions":100,"breadcrumbs":147,"categoryAnchor":157,"categoryFuturePath":158,"metaDescription":159,"availableHowToOs":160,"openOnDeviceLinks":161,"cannotOpenReasons":177,"cannotOpenFixes":178,"convertOptions":179,"securityAffiliateMessaging":180,"securityAffiliates":181},false,"wasm","WebAssembly binary module","web","Web","2026-06-12T07:58:15.956Z",55,".wasm is the binary module format for WebAssembly, designed to run fast and efficiently in web browsers and other runtimes. You typically “open” it by loading it in a WebAssembly runtime (often via JavaScript in a browser) or by running it with a standalone runtime such as Wasmtime.",[13,14,15,16,17],"windows","mac","linux","ios","android","To open .WASM files on Windows, if you expect it to run as part of a website: open the site in a modern browser; the page’s JavaScript will load the .wasm module via the WebAssembly API.","To open a .wasm file, you usually load it as a WebAssembly module in a web page (through the WebAssembly APIs) or run it with a WebAssembly runtime outside the browser (for example, Wasmtime). Double-clicking a .wasm file normally won’t do anything useful because it’s a compiled binary module, not a document.","A .wasm file is a WebAssembly binary module. The WebAssembly core specification defines its binary encoding, including a module header and a sequence of sections. Browsers can fetch a “.wasm” resource via the WebAssembly Web API and then compile/instantiate it for execution.","WebAssembly (often shortened to “Wasm”) is a portable, low-level code format intended for safe and efficient execution. The W3C announced the WebAssembly specifications as W3C Recommendations and notes that the WebAssembly Web API executes a “.wasm” resource in the web platform.\n\nIn practice, .wasm files are rarely used alone; they are commonly paired with JavaScript “glue” code that loads the module, supplies imports, and calls exported functions. This is why users often encounter .wasm as part of a website or web app’s assets rather than as a standalone file to open.\n\nOutside the browser, .wasm modules can be executed by dedicated runtimes. For example, Wasmtime documentation describes running WebAssembly binaries (typically with the .wasm extension) as a way to use WebAssembly beyond the web.",[23,26,29,32,35,38],{"title":24,"url":25},"W3C Recommends WebAssembly to push the limits for speed, efficiency and responsiveness (2019) | W3C","https://www.w3.org/news/2019/w3c-recommends-webassembly-to-push-the-limits-for-speed-efficiency-and-responsiveness/",{"title":27,"url":28},"WebAssembly | MDN","https://developer.mozilla.org/en-US/docs/WebAssembly",{"title":30,"url":31},"WebAssembly Specification — WebAssembly 3.0","https://webassembly.github.io/spec/core/",{"title":33,"url":34},"Binary Format — WebAssembly 3.0","https://webassembly.github.io/spec/core/binary/index.html",{"title":36,"url":37},"Media Types | IANA","https://www.iana.org/assignments/media-types/",{"title":39,"url":40},"Introduction - Wasmtime","https://docs.wasmtime.dev/introduction.html",{"windows":42,"macos":46,"linux":50,"ios":54,"android":56},[43,44,45],"If you expect it to run as part of a website: open the site in a modern browser; the page’s JavaScript will load the .wasm module via the WebAssembly API.","If you want to run it locally outside the browser: install a WebAssembly runtime such as Wasmtime, then run it from a terminal (for example, by invoking the runtime with the .wasm file).","If you only need to inspect it: open it in a code editor or hex viewer to confirm it is a WebAssembly binary (it will be binary data, not readable source).",[47,48,49],"If it belongs to a web app: open the associated web page in a modern browser; the .wasm file is fetched and executed by the WebAssembly Web API.","To run it outside the web: install a WebAssembly runtime such as Wasmtime and run the module from Terminal using the runtime’s command.","To inspect the file: open it with a code editor or binary viewer (it won’t display as human-readable text).",[51,52,53],"If it’s part of a web project: open the related page/app in a modern browser; it will load the .wasm module through the WebAssembly APIs.","To execute it directly: install a WebAssembly runtime such as Wasmtime and run the module from your shell using the runtime.","For analysis: open it with a binary-capable editor/viewer to verify it is a WebAssembly module file.",[55],"iOS does not typically “open” .wasm as a standalone file; if it is used, it’s usually loaded by a web page in a browser. For direct execution or deeper inspection, transfer the file to a desktop OS and use a WebAssembly runtime or developer tools.",[57],"Android does not commonly run .wasm as a standalone file; it is typically used by web apps in a mobile browser. For direct execution, move the file to a desktop OS and use a WebAssembly runtime such as Wasmtime.",[59,66,73],{"title":60,"description":61,"steps":62},"Double-clicking the file doesn’t open anything",".wasm is a compiled binary module and usually needs a runtime (browser WebAssembly APIs or a standalone runtime) rather than a document viewer.",[63,64,65],"Determine whether the .wasm came from a web app; if so, open the corresponding page/project instead of the file by itself.","If you need to run it locally, use a WebAssembly runtime (for example, Wasmtime) from a terminal.","If you just need to view what it is, open it in a code editor or binary viewer to confirm it’s a WebAssembly binary module.",{"title":67,"description":68,"steps":69},"It won’t run by itself (missing imports / needs JavaScript)","Many WebAssembly modules are designed to be instantiated with specific imports provided by JavaScript (or another host environment). Without the expected host functions and setup, instantiation or execution can fail.",[70,71,72],"Look for companion files in the same project (often JavaScript that loads the .wasm module via WebAssembly APIs).","Run it in the intended environment (e.g., the web app or the runtime/toolchain it came with) rather than treating it as a standalone executable.","If using a standalone runtime, ensure you are invoking it in a way that matches the module’s expectations (exports/entry points and imports).",{"title":74,"description":75,"steps":76},"Web server serves the wrong content type for .wasm","When delivered over the web, a .wasm file should be served with the appropriate registered media type. Incorrect server configuration can cause loading/compilation issues in browsers.",[77,78,79],"Check the server’s response headers for the .wasm request and verify the Content-Type is correct.","Configure your web server to serve .wasm with the registered media type for WebAssembly.","Use browser developer tools (Network tab) to confirm the .wasm resource is fetched with the expected headers.",[81,82,83],".wasm is executable code in a sandboxed WebAssembly environment; treat untrusted .wasm like untrusted scripts—loading it in a web page or runtime can run attacker-controlled logic.","A .wasm module can still trigger security-relevant behavior through the host environment (imports and APIs provided by JavaScript or a runtime), so the effective risk depends on what capabilities the host gives it.","Because .wasm is a binary format, bugs in compilers, runtimes, or toolchains that parse/compile it can be a security risk; prefer well-maintained, standards-based implementations and keep runtimes/browsers updated.",[85,88,91,94],{"question":86,"answer":87},"Is a .wasm file the same as JavaScript?","No. WebAssembly is a separate binary module format designed for efficient execution; it is often used alongside JavaScript, which typically loads and interacts with the .wasm module via WebAssembly APIs.",{"question":89,"answer":90},"Can I open a .wasm file in a browser by clicking it?","Usually not in a meaningful way. Browsers execute .wasm when it is loaded by a web page using the WebAssembly Web API; the module is typically fetched as a resource and instantiated by JavaScript.",{"question":92,"answer":93},"What is the official media type (MIME type) for .wasm?","The WebAssembly specification recommends a media type, and IANA is the authoritative registry for registered media types. In practice, configure servers according to the IANA registration and the WebAssembly spec guidance for serving WebAssembly binaries.",{"question":95,"answer":96},"Can .wasm run outside the browser?","Yes. WebAssembly modules can be executed by standalone runtimes; for example, Wasmtime documentation describes running WebAssembly binaries (typically with the .wasm extension) outside the web.",[],[99],"application/wasm",[101,107,112,118,124,129,135,141],{"ext":102,"name":103,"category":7,"categoryName":8,"popularity":104,"summary":105,"howToOs":106},"jsx","JSX (JavaScript XML) source file",75,".jsx is JavaScript source code that includes JSX, an XML-like syntax commonly used to write React UI components. You open it in a code editor (for viewing/editing) and typically compile it to plain JavaScript with tools like Babel or TypeScript.",[13,14,15,16,17],{"ext":108,"name":109,"category":7,"categoryName":8,"popularity":10,"summary":110,"howToOs":111},"war","Web Application Archive (WAR)",".war is a Web Application Archive used to package Java/Jakarta servlet-based web applications for deployment on a servlet container (for example, Apache Tomcat or Jetty). It is a ZIP-based Java archive that contains application classes, libraries, and web resources in a standard layout.",[13,14,15,16,17],{"ext":113,"name":114,"category":7,"categoryName":8,"popularity":115,"summary":116,"howToOs":117},"css","CSS stylesheet",39,".css is a Cascading Style Sheets (CSS) text file used to control the look and layout of web pages. You can open it in any text editor, and it is commonly edited with code editors that understand CSS.",[13,14,15,16,17],{"ext":119,"name":120,"category":7,"categoryName":8,"popularity":121,"summary":122,"howToOs":123},"mht","MHTML (Web Archive) file",35,".mht is an MHTML web archive that saves a complete web page (HTML plus images/CSS and other referenced files) into a single file. It’s commonly opened in modern web browsers such as Google Chrome and Microsoft Edge.",[13,14,15,16,17],{"ext":125,"name":126,"category":7,"categoryName":8,"popularity":121,"summary":127,"howToOs":128},"mhtml","MHTML (MIME HTML) Web Archive",".mhtml is a single-file web page archive that packages an HTML document together with its images, stylesheets, and other resources using a MIME multipart structure.",[13,14,15,16,17],{"ext":130,"name":131,"category":7,"categoryName":8,"popularity":132,"summary":133,"howToOs":134},"htm","HTML document",34,".htm is an HTML document (a text file that describes a web page). You can usually open it in any modern web browser or a plain-text/code editor.",[13,14,15,16,17],{"ext":136,"name":137,"category":7,"categoryName":8,"popularity":138,"summary":139,"howToOs":140},"svgz","SVGZ image",27,".SVGZ is a gzip-compressed SVG (Scalable Vector Graphics) image. It opens in most software that supports SVG, including modern web browsers and vector editors that can read compressed SVG.",[13,14,15,16,17],{"ext":142,"name":143,"category":7,"categoryName":8,"popularity":144,"summary":145,"howToOs":146},"xml","XML document",26,".XML files are used for web pages, browser rendering, and front-end assets. Open with web browsers, code editors, or build tools for web development. This guide covers opening methods, troubleshooting, and security best practices. Common MIME type: application/xml.",[13,14,15,16,17],[148,151,154],{"label":149,"to":150},"Home","/",{"label":152,"to":153},"File Extension Index","/file-extension",{"label":155,"to":156},".WASM","/file-extension/wasm","category-web","/category/web","Learn what .WASM files are, how to open them on every platform, common fixes, and security best practices.",[13,14,15,16,17],[162,165,168,171,174],{"os":13,"label":163,"to":164},"Open .WASM on Windows","/how-to/open-wasm-on-windows",{"os":14,"label":166,"to":167},"Open .WASM on Mac","/how-to/open-wasm-on-mac",{"os":15,"label":169,"to":170},"Open .WASM on Linux","/how-to/open-wasm-on-linux",{"os":16,"label":172,"to":173},"Open .WASM on iOS","/how-to/open-wasm-on-ios",{"os":17,"label":175,"to":176},"Open .WASM on Android","/how-to/open-wasm-on-android",[60,67,74],[63,64,65],[],"untrusted_source",[182,186],{"name":183,"description":184,"affiliateUrl":185},"Avast","Avast offers free and premium antivirus software that protects against viruses, malware, ransomware, and phishing. Scan files before opening them to ensure safety.","https://www.avast.com/lp-aff-consumer-store?expid=inf601",{"name":187,"description":188,"affiliateUrl":189},"Norton","Norton 360 delivers comprehensive antivirus protection, VPN, and identity theft monitoring. Scan files for threats before opening to keep your device secure.","http://buy.norton.com/aff_home?utm_campaign=en-ww_nor_n36_aff_nas_nau_nah_cj_nad_low:_sec_nat_mktc_norton_360"]