UnifiedPush: reach a phone that has no Google in it.

Web push on Android is Firebase's, so a phone without Google Play Services —
GrapheneOS, CalyxOS, any de-Googled Android — cannot be woken by a web app at
all. UnifiedPush is the way that doesn't involve Google: the user runs a
distributor (ntfy and friends), apps ask it for an endpoint, and whoever
wants to reach the device POSTs to that endpoint.

THE WRAPPER speaks the protocol directly — four broadcasts each way, so it
pulls in no library; an APK this small has no business growing a Kotlin
runtime for eight intents. It asks the distributor on every launch (the call
is idempotent, and it's how a distributor installed later gets noticed),
raises a notification when a message arrives, and acknowledges it so the
distributor stops resending.

THE ENDPOINT reaches the web app on the launch URL as ?up=, the same road
payment intents already travel — because the distributor talks to the app and
only the web app knows which pubkeys are worth watching. It's registered with
the notifier in place of a browser subscription, for notifications and for
NWC alike, and needs neither permission nor push service.

THE NOTIFIER sends to either kind: one deliver() that POSTs the payload to a
UnifiedPush endpoint, or hands it to web-push as before. Same payloads, same
404/410 pruning. The endpoint is the only secret there, so it's never logged
in full.

Verified: a POST to a live ntfy endpoint delivers the payload byte for byte,
so the app parses exactly what the notifier sent; the APK builds, carries the
receiver, and is signed with the certificate assetlinks already pins (v1.6).
tools/unifiedpush-test.js drives a browser with no push service and checks
the endpoint is taken off the URL, kept, and registered.

Honest about the limit: a UnifiedPush message wakes the ANDROID app, not
Chrome's service worker, and the wallet's keys live in the browser's storage
where nothing here can reach them. So a zap request arrives as a notification
you tap, and the wallet answers when it opens — one tap instead of none.
Automatic answering while closed still needs a browser with a push service.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_019mrt228Upn9nNCwGixzSLx

1 files changed, 7 insertions, 0 deletions

diff --git a/android/app/src/main/res/values/strings.xml b/android/app/src/main/res/values/strings.xml
index 8a4876a..8eca245 100644
--- a/android/app/src/main/res/values/strings.xml
+++ b/android/app/src/main/res/values/strings.xml
@@ -1,6 +1,13 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
   <string name="app_name">Coinos</string>
+  <!-- UnifiedPush notifications: what a woken app says before you open it.
+       The payload names a category; the wallet itself has the detail. -->
+  <string name="push_generic">Something happened in your wallet</string>
+  <string name="push_payment">You were paid</string>
+  <string name="push_dm">New message</string>
+  <string name="push_chat">New message in a group</string>
+  <string name="push_nwc">An app is asking to pay — open Coinos to approve</string>
   <!-- must match the site's /.well-known/assetlinks.json for URL-bar-less TWA -->
   <string name="asset_statements">
     [{