How to Check If Your Site Meets Core PWA Requirements

You’ve built a web app and want users to be able to install it to their home screen like a native app — that’s the promise of a Progressive Web App — but the install prompt just isn’t showing up, and there’s no obvious error message telling you why. PWA installability depends on meeting several specific technical requirements simultaneously, and missing even one of them silently prevents the install prompt from ever appearing, with no built-in diagnostic pointing you to which one.

Getting PWA installability right isn’t about writing especially complex code — it’s about correctly satisfying a checklist of specific requirements, and the failure mode when you miss one isn’t an error, it’s just silence.

What core PWA installability actually requires

A valid web app manifest — a JSON file describing the app’s name, icons, start URL, and display mode — needs to be correctly linked and formatted. A registered service worker needs to be active, since it’s what enables offline functionality and background behavior that browsers require for installability. The site needs to be served over HTTPS, since browsers won’t offer installation for insecure connections. And the manifest needs to reference properly sized icons, since browsers check for specific icon dimensions to use across different display contexts.

All four of these need to be true simultaneously — missing any single one means no install prompt, and because there’s no clear browser-level error message pointing to the specific missing piece, diagnosing which requirement isn’t met means checking each one individually.

Why people get stuck here

• No install prompt with no clear reason why. Browsers don’t typically surface a specific error explaining which PWA requirement is missing — the prompt simply doesn’t appear.
• Manifest formatting or linking issues. A manifest file that’s malformed, or not correctly linked from the page’s HTML, silently fails to register even if the file itself exists.
• Service worker registered incorrectly or not at all. Since the service worker enables key PWA behavior, a missing or improperly scoped one blocks installability regardless of everything else being correct.
• Missing or incorrectly sized icons. Browsers expect icons at specific dimensions referenced in the manifest, and missing the right sizes can silently fail the installability check even with everything else in place.

What a good PWA compatibility checker looks like

Checks each core requirement individually

Since any one missing requirement blocks the whole install prompt, checking manifest, service worker, HTTPS, and icons separately — rather than a single pass/fail result — actually tells you where to look.

Shows an example of a correct result

Seeing what a passing check actually looks like helps you understand what “correct” means for each requirement, not just that something failed.

Covers all four core requirements together

Manifest, service worker, HTTPS, and icons are the foundational installability requirements, and checking all four in one pass avoids missing one while fixing another.

Common mistakes to avoid

• Assuming a missing install prompt means one obvious bug, when it’s more often one of several independent requirements not being met.
• Forgetting that HTTPS is a hard requirement — installability simply won’t work on an insecure connection regardless of everything else being correct.
• Linking a manifest file incorrectly from the page’s HTML, so the browser never actually finds it even though the file itself is valid.
• Registering a service worker with a scope that doesn’t actually cover the pages where installability is expected.
• Providing icons at the wrong dimensions, which can silently fail the check even when an icon file is present and referenced.

How to do it with PWA Compatibility Checker

Online Tool Store’s PWA Compatibility Checker checks your site’s core requirements directly.

1. Open the PWA Compatibility Checker tool.
2. Enter the URL of the site you want to check.
3. Review the individual pass/fail results for manifest, service worker, HTTPS, and icons.
4. Fix whichever specific requirement is flagged, then recheck.

Because it breaks down each requirement separately, you get a clear starting point instead of guessing why the install prompt isn’t showing.

Frequently asked questions

Why doesn’t my browser tell me why the PWA install prompt isn’t appearing?

Most browsers don’t surface a specific diagnostic message for this — the installability check happens internally, and failing any one requirement just means the prompt silently doesn’t show, which is exactly why a dedicated checker that breaks down each requirement individually is useful.

Is HTTPS really a strict requirement for PWA installability?

Yes — browsers require a secure connection for PWA installation as a security measure, and there’s no way around this requirement short of actually serving the site over HTTPS.

What’s the most commonly missed PWA requirement?

It varies, but manifest linking issues and service worker registration problems are both common — since neither produces an obvious error message, they’re easy to overlook even when a developer believes they’ve set everything up correctly.

Final thought

PWA installability is a checklist problem, not a complexity problem — get all four core requirements right simultaneously, and check them individually rather than guessing which one is silently blocking the install prompt.

Try the free PWA Compatibility Checker tool