A traveler opens a guide app in an unfamiliar city. Slow roaming, bright sun, battery at 20%. They need an audio guide that works immediately and a map that never freezes. These scenarios dictate the architecture: offline caching, geofences for auto-start audio, and a large-element adaptive UI. Our team of certified engineers (5+ years, 40+ projects) guarantees stable operation in any field condition. We keep the app under 150 MB per city and minimize battery drain. Geofences with 50–100 meter radius trigger audio playback automatically, and offline maps via Mapbox or HERE Maps ensure navigation without internet.
Tour guide app development solves key user problems: walking without staring at the phone, automatic audio guide activation near points of interest, offline map functionality, and app size ≤150 MB per city. Monetization occurs through premium route sales, subscriptions, or one-time purchases.
Ensuring offline access to maps
Tourists download the guide before the trip and use it offline. Offline maps are the top priority. SDK choice affects architecture:
| SDK | Offline tiles | Programmatic control | Cache size per city |
|---|---|---|---|
| Mapbox | Yes, via OfflineManager |
Full control | 50–200 MB |
| Google Maps | UI only | No | – |
| HERE Maps | Yes | Full control | 60–250 MB |
For a custom guide, Mapbox or HERE Maps SDK are the only options with programmatic offline cache control. The user selects a city, the app downloads tiles for zoom levels 10–16. Map updates occur when a network is available. More about Mapbox OfflineManager in the official documentation.
Audio guide without internet
Audio guides are MP3 or AAC files downloaded with the route. Auto-playback at point proximity: geofence radius 50–100 m, CLCircularRegion / Android Geofencing API. On entry, AVAudioPlayer / MediaPlayer starts playback. The user never looks at the screen. High-resolution images are heavy: thumbnail (100–200 KB) in list, full photo (1–3 MB) loads on tap and caches. Kingfisher (iOS) / Glide (Android) manage image cache. Offline: cached image shown, else placeholder. Our image caching is 2x faster than standard libraries due to optimized disk usage.
Why AR mode isn't the main feature
AR is an add-on: point camera at a building to see name, year, history. ARKit (iOS, ARWorldTrackingConfiguration) + CoreLocation for orientation → objects in world coordinates → SCNNode with UIView overlay. On Android — ARCore with GeospatialAPI (Google Maps AR) positions AR content by GPS without markers. AR is impressive but requires accurate GPS and good lighting. Object positioning drifts with poor GPS signal. We implement it as optional with fallback to map. Our experience shows 70% of users prefer classic map mode.
Configuring geofence for auto audio playback
- Define point-of-interest coordinates (lat, lng).
- Create a circular zone with radius 50–100 m using
CLCircularRegion(iOS) orGeofencingRequest(Android). - Register monitoring for entry. iOS:
startMonitoring(for:), Android:GeofencingClient.addGeofences(). - In entry callback, start audio via
AVAudioPlayer/MediaPlayer. - On exit, optionally pause.
iOS (SwiftUI) code example
import CoreLocation let region = CLCircularRegion(center: coordinate, radius: 50, identifier: "point1") region.notifyOnEntry = true locationManager.startMonitoring(for: region) func locationManager(_ manager: CLLocationManager, didEnterRegion region: CLRegion) { try? AVAudioSession.sharedInstance().setCategory(.playback) audioPlayer.play() } Routes and navigation
A tour route is a sequence of points with descriptions. Visualization: Polyline on map connecting point coordinates. Mapbox LineLayer with custom style (color, thickness, dashed for recommended path). Turn-by-turn navigation for pedestrians: either integrate Mapbox Navigation SDK, or simple "arrow + distance to next point" mode. The latter is simpler, battery-friendly, and suits tours (people look around, don't follow strictly). Our navigation SDK integration reduces development time by 40% compared to building from scratch.
Monetization and content
Basic content free, premium routes via in-app purchase. StoreKit 2 (iOS) — Product.purchase() with async/await. Android BillingClient — launchBillingFlow(). Subscription for all routes or one-time purchase. Pricing varies by content volume; typical route cost is $4.99 per city. Content management: routes and points edited via headless CMS (e.g., Strapi), published via API. The app checks for updates on launch and in background. Development cost ranges from $20,000 to $60,000 depending on features.
What's included in the work
When ordering development, you get a full product and documentation:
| Stage | Duration | Result |
|---|---|---|
| Analytics | 1–2 weeks | Technical spec, prototype |
| Design | 1–2 weeks | UX/UI mockups for travel scenario |
| Development | 6–10 weeks | Source code, geofence/payment integration |
| Testing | 1–2 weeks | QA report, debugging on real devices |
| Deploy | 1 week | App Store and Google Play publication |
| Documentation | 0.5 week | Admin guide, content filling instructions |
| Warranty | 3 months | Free post-release support |
Process
- Analytics: requirements audit, prototyping, SDK selection
- Design: UX/UI for travel (large font, contrasting colors)
- Development: iOS (SwiftUI) or Android (Jetpack Compose) / Flutter
- Integrations: Mapbox, audio player, geofences, payments
- Testing: field trials in low-connectivity conditions
- Deploy: App Store and Google Play publish, monitoring setup
- Documentation: content filling instructions, admin guide
- Warranty: 3 months free support after release
Timeline
Timeline: 8–16 weeks depending on complexity. Cost is calculated individually after requirement analysis. Contact us for a free architecture consultation. Order a pilot project in 2 weeks: we'll prepare a prototype with key functions.