Overview

application/manifest+json is the media type for the web app manifest file of a Progressive Web App. It declares the app name, icons, start URL, display mode, theme color, and more so a browser can 'install' the site to the home screen.

Details

You link it from HTML with `<link rel="manifest" href="/site.webmanifest">`. The conventional extension is `.webmanifest`, though `.json` is also common. The file is a JSON object with name, short_name, icons (multiple resolutions), start_url, display (standalone/fullscreen/browser), background_color, theme_color, and so on.

For a browser to show an install prompt the manifest must be valid, usually alongside HTTPS, a service worker, and a proper icon set. Fetching the manifest cross-origin with credentials may require handling the `crossorigin` attribute. If a server serves this file as text/plain or application/json, some browsers and audit tools (Lighthouse) may fail to recognize it as a manifest.

Syntax

e.g. Content-Type: application/manifest+json

File extensions

Notes

• Without the exact Content-Type (application/manifest+json), some browsers and PWA audits warn; register .webmanifest in your server's MIME map.
• If start_url or scope paths disagree with the actual deployment path, the installed app launches on the wrong page.
• It is fundamentally JSON, so the same UTF-8 and syntax rules apply, and a syntax error fails installability.

Related types

Related headers