Across Us
See you somewhere.
Friends’ cities, overlapping plans and group trips, in one quiet iPhone app.
English · 简体中文
200+ cities, each with its own emblem.
Friends move.
Across Us keeps their cities, plans and flights in one place, so a chance to meet doesn’t slip past. No live map, no GPS trail: just the city each friend chose to share, and when they shared it.
Everyone lands together.
Invite friends to a Trip and watch every flight land where you’re meeting.
- Every flight, one tap away. Tap anyone for their boarding pass: local times, terminal and the flight home. Each traveler manages their own.
- A nudge when it helps. Flight-change alerts, morning reminders, and a tap to remind a friend who hasn’t added their flight.
- Room for plans to change. Members can leave; the creator can remove members or delete the Trip.
On your Home Screen.
Private by design.
Full policy: acrossus.app/privacy
Free, and personal.
I built Across Us for me and my friends: scattered across cities, always trying to line up the next visit. It’s entirely free. No subscription, no ads, nothing to unlock. Just a quieter way to keep up with each other, and to meet again.
For me and my friends. For you and yours.
— Yang, who made Across Us
Under the hood
| Layer | Stack |
|---|
| App | SwiftUI · WidgetKit (small, medium, large) · iOS 18+ · English and 简体中文 |
| Backend | Supabase Postgres with versioned migrations · Edge Functions: api, push-worker, trip-worker, ops-monitor |
| Notifications | APNs, delivered per device from an outbox with retries |
| Flights | AeroDataBox lookups and status refresh |
| Web | acrossus.app on Cloudflare Pages, with Pages Functions for invite links and Universal Links |
| CI | GitHub Actions: backend tests, Debug / Staging / Release builds, unit tests |
WhereIsMyFriend/ SwiftUI app: App, Core, Features (Friends, Trips, TravelPlans, …)
WhereIsMyFriendWidget/ WidgetKit extension
WhereIsMyFriendTests/ Unit tests
WhereIsMyFriendUITests/ UI tests
supabase/ Migrations, Edge Functions, seed, backend tests
site/ functions/ acrossus.app and its Pages Functions
docs/ Design spec, API contract, release notes, reviews
Run it locally
You’ll need Xcode 27 (iOS 27 SDK). The app deploys to iOS 18 and later.
- Open
WhereIsMyFriend.xcodeproj.
- Pick the WhereIsMyFriend scheme and any iPhone simulator.
- Build and run.
Debug builds run on a local demo repository, so the whole app works without a server. Pass -useRemoteAPI to talk to a configured backend instead.
npm ci && npm run backend:test
xcodebuild -project WhereIsMyFriend.xcodeproj -scheme WhereIsMyFriend \
-sdk iphonesimulator -destination 'generic/platform=iOS Simulator' \
CODE_SIGNING_ALLOWED=NO build
Your friends are out there. Make room for the next hello.
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© 2026 Across Us
