Web App Manifest Checker
Fetch a site's manifest and check the fields a browser needs before it will offer to install.
About this tool
Finds a page's web app manifest, fetches it, and checks whether it has what a browser needs.
**Every failure here is silent.** A manifest declared at a URL that 404s, or one that is not valid JSON, produces no error a visitor could see — the browser reads it, gives up, and simply never offers to install. There is no warning and no report, so the usual conclusion is that installation was never configured, when in fact it was configured and is broken.
Chrome requires `name` or `short_name`, a `start_url`, a `display` that is not `browser`, and icons at 192 and 512 pixels. Missing any one of them and the install prompt does not appear.
The icon URLs are listed but not fetched. A manifest referencing an icon that does not exist is a real failure and finding it needs one request per icon, which this tool does not make.
Common questions
Do I need a manifest?
Only if you want the site installable, or want control over the icon and colours when somebody adds it to a home screen. It is not a ranking factor and an ordinary site loses nothing without one.
Why does the install prompt never appear?
Usually a missing field or icon size, or a service worker that is absent. Chrome needs name, start_url, a display other than browser, icons at 192 and 512, and HTTPS — and it tells nobody which one is missing.
Why does my manifest fetch fail on the live site?
Nearly always CORS. A manifest on a different origin needs crossorigin="use-credentials" on the link element, and without it the browser fetches it anonymously and may be refused.
What is a maskable icon?
One with padding so Android can crop it into whatever shape the launcher uses. Without a maskable icon your logo gets clipped at the edges on some devices, and looks fine on the one you tested with.