How to use it
- Type the Name and the Short name, then the Start URL and the Scope of the app.
- Pick the Display mode, and type the Background colour and the Theme colour as hex colours.
- Write one icon per line under Icons: the address, then the sizes, the type and the purposes, separated by bars.
- Save the text under manifest.webmanifest, and fix each warning listed under Installability checks.
What the members mean
The manifest is a JSON file. Its members are described in the W3C Web Application Manifest (section 1). Only the members you fill in are written, so an empty field leaves its member out. The display mode decides how the browser shows the app; if the browser does not support a mode, it uses the next one of this chain (section 6): fullscreen, then standalone, then minimal-ui, then browser.
A start URL that is on another origin than the page is ignored, because the spec asks for the same origin. A scope is used only when it contains the start URL; otherwise browsers use the scope that is the start URL without its file name, query and fragment.
What the warnings check
MDN lists the members that Chromium-based browsers need before they offer to install a web app: a name or a short name, icons with a 192px and a 512px icon, a start URL, and a display mode. It also says the site must be served over https, or from localhost, and that a service worker is not required. Firefox does not install a web app from a manifest file on desktop.
The tool checks the members above and the scope rule. It does not test the icon files, the HTTPS address or the link on your pages; those are yours to confirm.
The default values
With the values the page opens with, the manifest has the members below. The checks show no warning, because the name, the start URL and both icon sizes are there.
| Member | Value |
|---|---|
| name, short_name | Notes, Notes |
| start_url, scope | /, / |
| display | standalone |
| background_color, theme_color | #ffffff, #1f6feb |
| icons | 192x192 and 512x512 PNG files; the 512 icon has the purpose any maskable |
Frequently asked questions
Where do I save the manifest file?
Save it in the root of the site, or in the folder of the app, and name it manifest.webmanifest. Then link it from every page of the app with a link element whose rel is manifest, as MDN describes.
Do I need a service worker to install the app?
No. MDN says a service worker is not a requirement for a PWA to be installable, although many apps use one to work offline. The site still has to be served over https, or from localhost.
Which icon sizes do I need?
MDN lists a 192px and a 512px icon for Chromium-based browsers. Add the sizes as WIDTHxHEIGHT, separated by spaces when one file has several. An SVG file can have the size any.
What is the difference between the short name and the name?
The name is the full name of the app. The short name is for the places where space is short, such as the label under the icon on a home screen. Give at least one of them; this tool warns when both are empty.
Why does the tool warn about the scope?
A scope is used only when it contains the start URL (W3C section 1). If the start URL is outside the scope, browsers ignore the scope and use their default one, so the app may open outside the area you meant.
Sources
- W3C, Web Application Manifest (Working Draft, 6 November 2026): sections 1, 2 and 6
- MDN, Making PWAs installable
- MDN, display member of the web app manifest
- MDN, icons member of the web app manifest
Figures and text last checked on Tuesday, November 10, 2026.