Glossary · Web Development

Web App Manifest

A web app manifest is a JSON file that tells browsers a site's name, icons, colors and display mode so it can be installed like an app.

Updated October 6, 2026

A web app manifest is a JSON file, usually manifest.webmanifest, that describes a web application to the browser. It supplies the name, icons, start URL, theme color and display mode that the browser uses when a user installs the site to a home screen or desktop.

Why it matters

The manifest is one of the requirements for a site to be installable as a progressive web app, together with HTTPS and, in some browsers, a registered service worker. It controls the installed experience: the icon, the splash screen and whether the app opens in a standalone window without browser controls.

Example

<link rel="manifest" href="/manifest.webmanifest">
{
  "name": "Status Board",
  "short_name": "Status",
  "start_url": "/?source=pwa",
  "display": "standalone",
  "background_color": "#ffffff",
  "theme_color": "#0a66c2",
  "icons": [
    { "src": "/icon-192.png", "sizes": "192x192", "type": "image/png" },
    { "src": "/icon-512.png", "sizes": "512x512", "type": "image/png" }
  ]
}

Common mistakes

  • Missing the 192 and 512 pixel icons, so the install prompt never appears.
  • A start_url that redirects or requires login, which can break launch.
  • Serving the file with the wrong status code or blocking it behind authentication.

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