What is MIME type "application/x-web-app-manifest+json"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

application/x-web-app-manifest+json is a MIME type for web app manifests. It uses the JSON format to provide essential information about a web application. This file details the app’s name, icons, start URL, and other settings needed for proper display and behavior.

The manifest supports progressive web apps (PWAs) and similar applications. It helps browsers know how to install the app and launch it in a more native-like mode.
Refer to the file type for WEBAPP for further details.

Main Use: Describes how a web app should be launched and installed.
Format: Written in JSON, making it easy for browsers to parse.
Additional Uses: Supports configuring app appearance, icons, and start-up behavior across multiple devices.

More technical insights are available on the MDN Web Docs.

Associated file extensions

.webapp

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-web-app-manifest+json

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-web-app-manifest+json">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');
    
    http.createServer((req, res) => {
      res.setHeader('Content-Type', 'application/x-web-app-manifest+json');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.webapp

FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.