Launch Handler API Demo - Online Control App Launch Behavior
Configure how your PWA launches: focus existing or create new. Test with the launch_handler manifest field.
UD5 Toolkit
Analyzing your site for beforeinstallprompt eligibility
All requirements must be met for beforeinstallprompt to fire
<link rel="manifest"> in document head
beforeinstallprompt event is fired by the browser when a Progressive Web App (PWA) meets all installation criteria. It signals that the browser is ready to show the native install prompt to the user. Developers can intercept this event using e.preventDefault() and trigger the prompt later, allowing custom install flows. This event is crucial for PWA adoption as it indicates the app is installable.
name (or short_name), icons array containing a 192x192 PNG icon and a 512x512 maskable icon, start_url, and display set to standalone, fullscreen, or minimal-ui. Additionally, a Service Worker must be registered and active. The user must also have sufficient engagement with the site (varies by browser).
window.addEventListener('beforeinstallprompt', (e) => { console.log('Install prompt available!', e); deferredPrompt = e; }); Also check Chrome DevTools under Application → Manifest for manifest validation and Application → Service Workers for SW status. The Lighthouse audit can also identify PWA issues automatically.
localhost and 127.0.0.1 without HTTPS. You still need a valid manifest and service worker. Use npx serve or python -m http.server for quick local testing. Chrome also provides a "Add to Home screen" option in DevTools under Application → Manifest for manual testing. For Safari, you need a Mac with Xcode to test iOS PWA installation.
beforeinstallprompt. Safari on iOS/iPadOS uses a different mechanism (WebKit's apple-mobile-web-app-capable meta tag) and does not fire this event. Firefox does not support PWA installation on desktop. Firefox for Android has limited support. Always implement a fallback install flow for unsupported browsers.
name or short_name (app name), icons (array with at least one 192x192 and one 512x512 icon), start_url (the URL to load when the app launches), and display (should be standalone for a native-like experience). Recommended: theme_color, background_color, description, scope, and categories.
beforeinstallprompt again. This period is typically around 90 days for the mini-infobar and 3 months for the full prompt, though the exact duration is not publicly documented and may change. To reset during development, clear site data in Chrome or use an incognito window. On Android, clearing Chrome's storage for the site can also reset this.
Configure how your PWA launches: focus existing or create new. Test with the launch_handler manifest field.
Check if a password appears in the Have I Been Pwned database using k‑Anonymity. Only the first 5 characters of the hash are sent.
Enter foreground and background colors to instantly see the contrast ratio and pass/fail for AA and AAA. Simple and fast.
Check which cipher suites a website supports and identify weak or outdated ones. Quick security audit from your browser.
Check if your page triggers the beforeinstallprompt event. Simulate the install flow. Debug PWA installability.
Register a periodic background sync to fetch fresh data even when the tab is closed. Understand the API and limits.
Fetch a site’s HSTS header and validate its syntax, max‑age, and subdomain flags. Ensure your site enforce HTTPS.
Enter an API URL and quickly check its HTTP status code and response time. See response headers and body. Browser fetch.
Type any character and see how it renders in different font stacks. Detect missing glyphs and fallback behavior.
Enter a URL and get a one‑page report of titles, description, headings, image alts, and broken links. All from browser.
Look at HTTP headers and JavaScript objects to guess which browser extensions might be installed. For awareness.
Enter a package name and version range to see all satisfying versions from the registry. Understand ^ and ~.
Check if an IBAN has the correct length and structure for its country. Early validation, no bank connection.
Drop an image that might have wrong extension and see its real format (JPEG, PNG, WebP) based on header bytes.
Enter a URL and see its favicon at all standard sizes. Check if it's properly defined. SEO basic check.
Check if a number of the form 2^p‑1 is a Mersenne prime. Quick Lucas‑Lehmer test simulation for small p.
Click for a random drawing or sketching idea. Characters, objects, scenes. Beat artist's block. All local.
Get three random words as a creative writing prompt. Challenge yourself to use them in a story. No repeat for a while.
Trace the full redirect path of a URL. See every hop, status code, and final destination. Detect broken chains.
Paste your email body and subject, and get a spam score based on common trigger words and patterns. Improve your cold outreach.
Type a word to see all its homophones with definitions. Avoid embarrassing mistakes (their/there/they’re). Static dictionary.
Enter a year to check if it is a leap year. Shows the rule explanation and next/previous leap years. Simple reference.
Find out if a word is an isogram (no repeating letters). Different types: first-order, second-order. Word nerd fun.
Check if a word or phrase is a palindrome (reads same forward and backward). Live validation and fun facts.
Check HTTP status codes for multiple URLs at once. Identify broken links and redirects. All requests made via browser fetch.
Preview the Gravatar image associated with any email address. Generate the correct Gravatar URL. Handy for avatar debugging.
Check if a website is globally reachable or experiencing issues. Status code and latency displayed. Quick browser-side test.
Enter a URL and see the full HTTP response headers returned by the server. Detect redirects and server type. Useful for SEO and web debugging.
Evaluate the strength of your passwords with a visual meter and detailed feedback. Check for length, complexity, and breached passwords. All analysis is client-side.
Check the contrast ratio between foreground and background colors to ensure web accessibility compliance. Get WCAG 2.1 AA/AAA pass/fail results instantly.