Web Share Target: register your PWA as a share destination

The system share sheet is the highest-intent surface on a mobile OS — someone actively wants to send content somewhere. Adding your PWA to that list is a 10-line manifest change.

Register in the manifest

{
  "share_target": {
    "action": "/share",
    "method": "POST",
    "enctype": "multipart/form-data",
    "params": {
      "title": "title",
      "text": "text",
      "url": "url",
      "files": [{ "name": "image", "accept": ["image/*"] }]
    }
  }
}

Handle the incoming POST

Your service worker intercepts the POST to /share. Read the FormData, stash it in IndexedDB, then redirect to a UI page:

self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url);
  if (event.request.method === 'POST' && url.pathname === '/share') {
    event.respondWith((async () => {
      const form = await event.request.formData();
      const payload = {
        title: form.get('title'),
        text: form.get('text'),
        url: form.get('url'),
        image: form.get('image'),
      };
      const cache = await caches.open('share');
      await cache.put('/share-payload', new Response(JSON.stringify(payload)));
      return Response.redirect('/share-view', 303);
    })());
  }
});

Testing

Install the PWA on an Android device, share any content from Chrome or the gallery, and your app appears in the sheet. Chrome DevTools → Application → Manifest validates the share_target JSON before you install.

Common pitfalls

• Using GET when you need to accept files (they only work over multipart POST).
• Redirecting to a route that isn’t cached — fails offline.
• Expecting iOS support — it doesn’t exist. Use the Web Share API for outbound sharing on iOS.