Website Tools

Website PWA Checker

See how close a website is to being an installable progressive web app. The checker confirms HTTPS, reads the web app manifest and its installability fields, searches the page and up to six of the site’s own scripts for a service worker registration and checks that the service worker file answers, and looks at the mobile viewport, Apple touch icon and theme colour. A weighted score summarises what is in place and what is missing.

  • Encrypted connection
  • No sign-up
  • Free to use

Checks what can be seen from the outside: HTTPS, manifest, service worker registration and icons. Offline behaviour needs a real browser test.

How to use Website PWA Checker

  1. Enter the page address.
  2. Click “Check PWA”.
  3. Read the score and checks.
  4. Test offline behaviour in your browser.

Website PWA Checker features

HTTPS

Required for service workers.

Manifest

Installability fields.

Service worker

Registration and file status.

Mobile signals

Viewport, icons, colours.

Safe fetching

Public addresses only, with size and time limits.

Score

Weighted readiness.

When to use Website PWA Checker

  • Planning a PWA.
  • Checking a PWA plugin.
  • Debugging missing install prompts.
  • Comparing sites.

Website PWA Checker FAQ

Can it test offline mode?

No. Offline behaviour depends on what the service worker caches; test it in developer tools with the network off.

Why might a service worker be missed?

If it is registered from a script bundle loaded later, or from a script on another domain.

Do I need a service worker to install?

Chrome no longer requires one, but it is needed for offline use and reliable performance.

Does Safari support PWAs?

iOS supports adding web apps to the home screen, using the Apple touch icon.

What makes a PWA

A progressive web app is a website that can be installed and keeps working on poor connections. HTTPS, a manifest and a service worker are the three building blocks.

Start with the manifest; it is the quickest win.

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.

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