Website Manifest Checker
Validate the manifest that makes a website installable. The checker follows the page’s manifest link, parses the JSON and checks the fields browsers need – a name or short_name, start_url, a display mode such as standalone and icons of at least 192 and 512 pixels – and the recommended ones: a short_name of up to 12 characters, a maskable icon, theme and background colours, a stable id and the right content type. It previews the app’s name and icon and shows the manifest.
- Encrypted connection
- No sign-up
- Free to use
How to use Website Manifest Checker
- Enter the page address.
- Click “Check manifest”.
- Fix the required fields first.
- Review recommendations.
Website Manifest Checker features
Installability fields
Name, start_url, display, icons.
Icon sizes
192 and 512 px or larger.
Maskable icons
For Android shapes.
JSON errors
Reported clearly.
Safe fetching
Public addresses only, with size and time limits.
Preview
Name and icon.
When to use Website Manifest Checker
- Making a site installable.
- Debugging PWA install prompts.
- Checking CMS PWA plugins.
- Brand consistency of app icons.
Website Manifest Checker FAQ
Where should the manifest be linked?
In the head of every page: <link rel="manifest" href="/manifest.webmanifest">.
What content type should it have?
application/manifest+json, though application/json works.
What is a maskable icon?
An icon with safe padding so Android can crop it into circles or squircles.
Is a manifest enough for installation?
Browsers also need HTTPS; a service worker improves the experience and offline use.
The manifest in brief
The web app manifest tells browsers how your site behaves when installed: its name, icon, colours and start page. Without the required fields, browsers do not offer installation.
Check the rest of the requirements with the Website PWA Checker.
How it works: our server downloads the page once through a guarded fetcher that only connects to public addresses, follows a limited number of redirects and stops after a size and time limit. The HTML is then analysed in your browser as inert text – scripts on the page never run and nothing is stored.
What it cannot see: content and resources that a page adds with JavaScript after it loads, pages behind a login, and servers that block automated requests. For those, open the page in your browser, use its developer tools, or paste the page source where the tool offers a paste option.
Use the results as a starting point: fix the items marked red first, review the yellow warnings in context, and run the check again after a change. Requests are rate-limited to keep the service fair; if you check many pages in a row, wait a few minutes.
Related checks on this site cover the rest of a technical review – speed and Core Web Vitals, security headers, structured data, accessibility and SEO signals – so you can work through a whole site audit one topic at a time.
Who it is for: site owners checking their own pages, developers debugging a release, SEO and marketing teams auditing clients or competitors, and students learning how the web works. No account or installation is needed, and the results are plain text and tables you can copy into a report or ticket.