WhoKnew Signal – Self-Hosted Web Push Notifications & PWA

For most sites, yes. WhoKnew Signal includes a Web App tab that generates and serves your manifest.json , configures your app icon, theme color, display mode, and injects required meta tags. Install on Phones ( [wkspn_install_buttons] ) is included in Pro for smart install buttons on Android and a guided iOS walkthrough. If your only reason for a separate PWA plugin was the manifest or iOS push setup, you can often use WhoKnew Signal alone.

If you are using a separate PWA plugin only for advanced offline caching strategies beyond Signal’s built-in network-first caching, you may keep both – they will not conflict.

Yes. iOS Safari 16.4+ supports Web Push when the site is installed to the Home Screen as a Progressive Web App (PWA). WhoKnew Signal configures everything required: the web app manifest, the Apple touch icon, and the meta tags that tell iOS how to display your site when installed.

To receive push notifications on iPhone or iPad: open your install page in Safari (use the Install on Phones shortcode or share manual steps), tap Add to Home Screen, open the installed app once, then grant notification permission. From that point on, they receive push notifications exactly like a native app. iOS support is included in the free version at no extra charge.

Chrome on iOS uses Apple’s WebKit rendering engine, not Chromium. Apple requires all iOS browsers to use WebKit, which means Chrome on iOS does not support Web Push. This is an Apple platform limitation that applies to every push notification plugin. The only way to receive push on iOS is through Safari with the site installed as a PWA.

No. WhoKnew Signal sends directly from your WordPress server to the browser’s delivery network – Chrome uses Google’s FCM, Firefox uses Mozilla’s relay, Safari uses Apple’s push service. These are free delivery pipes that every browser already uses. You do not pay for them, sign up for them, or store any data on them. Your subscriber list lives entirely on your server.

No. The free plugin operates entirely between your WordPress server and your visitors’ browsers. It does not phone home, send analytics, contact a license server, or make any external API calls. The only outbound connections it makes are the push notification deliveries themselves – sent directly from your server to the browser’s push delivery network. No WhoKnew server is ever involved.

Yes. Because subscriber endpoints are stored on your WordPress server (not on a push SaaS), you can migrate with WhoKnew Signal:

1. 01Export your VAPID keys (Settings > Backup & Migration > Export Key Backup)
2. 02Export your push subscribers (Settings > Backup & Migration > Download CSV – Pro feature)
3. 03Install WhoKnew Signal on the new server and restore the VAPID key backup before any visitors load the page
4. 04Import the push subscriber CSV (Settings > Backup & Migration > Import)

Your existing subscribers will continue receiving notifications without re-subscribing. This even works across domain changes.

Yes — and it happens automatically, with no effort from you or your visitors.

Switching push plugins normally means losing your subscriber list. Visitors who already granted permission to the old plugin can never be shown a native browser permission prompt again, so they silently disappear and cannot re-subscribe.

WhoKnew Signal detects this situation automatically. When a returning visitor has an active push subscription that belongs to a different plugin or service, WhoKnew Signal silently cancels that old subscription in the browser, then displays its own soft-ask popup. In most cases the browser already has permission granted and re-subscribes without a native dialog — the visitor simply clicks “Allow Notifications” on the WhoKnew popup and they are re-enrolled instantly. In some cases (for example if the browser reset the permission in the background, or on certain mobile Chrome versions) a brief native confirmation may still appear, but the visitor is never asked to grant permission from scratch.

This works for any service using the VAPID web push standard: OneSignal, Push Notifications for WordPress by magazine3, PushEngage, and others. Visitors who were never subscribed to any push service see the normal two-step popup flow (soft-ask, then native browser prompt) on their first visit. Existing WhoKnew Signal subscribers are never affected.

The free plugin discovers WooCommerce and other public post types in Settings; auto-send on publish is included for blog posts . WhoKnew Signal Pro unlocks auto-send for products and other post types, plus WooCommerce automation: order notifications to linked WordPress accounts (processing, completed, refund), abandoned cart recovery, and broadcast triggers for new products, back in stock, and price drops.

When a visitor subscribes, WhoKnew Signal stores their subscription status in both a browser cookie and localStorage . If the cache is cleared, whichever storage survives picks up immediately. If both are cleared but the browser’s underlying push subscription is still active, the plugin silently re-registers the subscriber in the background on their next visit. No popup re-appears, no duplicate entry is created.

No. The free plugin includes unlimited active subscribers . There is no 250-subscriber cap, no trial expiration on your list size, and no requirement to upgrade just to keep accepting new subscriptions. Upgrade to Pro when you want growth tools (Install on Phones, background sends, WooCommerce automation, segmentation, analytics, scheduling) – not because your audience outgrew a free quota.

Yes. The free version sends real push notifications to unlimited subscribers across supported browsers. The PWA manifest, welcome notification, auto-send on blog posts, and manual campaigns are included. Pro adds Install on Phones, background sends, rich images, additional post types, and the advanced features listed above. Very large broadcasts on shared hosting may need Pro background sending or a higher PHP time limit per request (see below).

Unlimited subscribers does not mean unlimited time in a single PHP request. On the free plan, each campaign runs in one server request while you keep the admin page open. Many shared hosts limit PHP to 30-60 seconds; sends above a few hundred subscribers may be cut off by your server. WhoKnew Signal Pro sends in background batches (many short runs) so delivery is not tied to one long request. You can also ask your host to raise max_execution_time, which may help on Free but you must still wait on the page until sending finishes.

Free delivers campaigns synchronously in the current browser request (fast for smaller lists). Pro can use instant send for lists below your Instant send threshold (Settings -> Background Send Performance) and background batched delivery for larger lists, with tunable batch size, parallelism, and time budget for your host.

WhoKnew Signal is built for privacy-conscious sites: subscriber data stays on your server, visitors consent via the browser permission prompt, and the plugin registers strictly necessary cookies with major consent tools (Complianz, Cookiebot, CookieYes, and others). The plugin does not collect names, email addresses, or IP addresses for push subscriptions. Each subscriber is stored as an opaque browser-generated endpoint plus browser type, platform, and subscription date. If a visitor is logged in, that endpoint may be linked to their existing WordPress account on your site (a reference your site already holds) so account-related notifications can reach the right device. Settings includes copy-paste privacy policy text for your site. You remain the data controller and should adapt that text to your practices.