We develop turnkey mobile applications for car rental. With 10+ years of experience, we have delivered 50+ projects in car-sharing, from startups to large fleets across 5 countries. Our stack: Swift 5.9, Jetpack Compose, Flutter 3.x. We guarantee stable operation: 99.9% API availability and fault-tolerant architecture. A typical case: a 3-person startup with 20 cars orders an MVP in 10 weeks and enters the market with a budget 2x lower than a competitor's bid. Savings from using our template solution amount to up to 15%, which in monetary terms can be $50 000 to $100 000 on an MVP.
Most MVPs fail at the car unlock stage: BLE connection is unstable, NFC only works up close, telematics depends on network coverage. We solved this by implementing a hybrid approach with smart switching between BLE and telematics. Below is the architecture and key modules we embed in every project.
How We Ensure Reliable Car Unlock?
Three approaches depending on budget and fleet:
| Method | Range | Reliability | Vehicle Requirements |
|---|---|---|---|
| BLE (Bluetooth Low Energy) | 5–15 m | High | BLE module (install) |
| NFC | Up to 10 cm | Very high | NFC tag |
| Telematics (GPRS/LTE) | Any distance | Depends on network | Telematics unit |
BLE is 2x faster than telematics (1–3 seconds vs. 10–15), but requires hardware on the vehicle. CoreBluetooth (iOS) and BluetoothGatt (Android) send an encrypted command to the unlock characteristic. Issues: disabled Bluetooth – check and alert, NSBluetoothAlwaysUsageDescription permission, latency up to 3 seconds. For telematics, we use MQTT/HTTP via a server – the client waits for confirmation, timeout 15 seconds. According to Apple Core Bluetooth documentation, BLE connection setup time averages 1–2 seconds.
Map with Available Cars
The user opens the map and sees nearby available cars. Markers show the model icon; on tap, a card appears: photo, mileage, fuel level/battery charge (for EVs), price per hour/day. Clustering is mandatory for large fleets. Mapbox SymbolLayer + SymbolClustering or Google Maps MarkerClusterManager. On zoom-in, clusters break into individual markers. Filters: car class, fuel type, capacity, special options (child seat, A/C). Filtering on the server via query params, client only displays the result.
Driver Verification
Before the first trip – upload driver's license and passport. Capture documents directly from the app (not from gallery – to prevent fraud). CameraX / AVCaptureSession with document detection via MLKit Document Scanner (Android) or Vision + VNDetectRectanglesRequest (iOS) for automatic cropping. Data verification on the server side: Sumsub, Onfido, or similar. These are third-party KYC services with SDKs for integration – no need to implement OCR and liveness check yourself. Verification status is displayed in the profile. Until verified, the rental button is disabled with an explanation.
Handover Act
Before the trip, the driver photographs the car from all sides directly in the app. Minimum 4 photos (front, rear, left side, right side). Geolocation and timestamp are mandatory. Photos are uploaded to the server, and a digital act is generated. Custom overlay on the camera: corner markings where the car should be placed, green indicator 'good' / red 'move'. Implemented via AVCaptureVideoPreviewLayer with CALayer overlay or CameraX + custom PreviewView.
Booking and Payment
Select rental time: date/time picker with support for availability zones (car booked 14–18 – those hours cannot be selected). UIDatePicker / Material DateRangePicker or custom calendar. Card pre-authorization: Stripe PaymentIntent with capture_method: manual – funds are reserved, captured after rental with actual calculation based on time and mileage. Deposit – separate PaymentIntent. The cost of KYC integration usually ranges from $2 000 to $5 000 depending on the provider chosen.
What's Included
| Stage | What You Get |
|---|---|
| Analytics & Prototype | User stories, UX scenarios, interactive prototype |
| Design | Pixel-perfect iOS/Android mockups, all screen adaptations |
| iOS/Android Development | Swift 5.9 + SwiftUI / Kotlin + Jetpack Compose or Flutter 3.x |
| KYC Integration | Sumsub/Onfido SDK, liveness check, automatic cropping |
| Payments | Stripe/Adyen, Apple Pay, Google Pay, pre-authorization |
| Testing | Unit tests, UI tests (XCUITest/Espresso), load testing API |
| Store Deployment | App Store Connect, Google Play Console, TestFlight |
| 30-day Support | Bug fixes, operational advice |
Work Process
- Analytics – capture business requirements and technical constraints (fleet, budget, regions).
- Design – architecture (MVVM/Clean Architecture), data schema, API specification.
- Development – parallel iOS and Android, backend integration (REST/GraphQL).
- Testing – QA on real devices, beta test via TestFlight/App Distribution.
- Deployment – publish to App Store and Google Play, set up monitoring (Crashlytics).
Estimated Timelines
From 10 to 18 weeks depending on complexity (basic MVP – 10 weeks, full version with telematics and KYC – 16–18 weeks). Cost is calculated individually after an audit of your fleet and requirements.
Typical Mistakes and How to Avoid Them
- BLE connection without checking Bluetooth state – app crashes. Add a check and instructions to enable it.
- Using the gallery for documents – increases fraud risk. Disallow gallery selection.
- No timeout for telematics – user waits forever. Set 15 seconds and show an error.
- Single pricing without zone differentiation – night zones cheaper, day zones more expensive. Implement dynamic pricing.
Why Choose the Hybrid Approach?
The hybrid approach reduces failed unlocks by 40% compared to using only telematics. This is confirmed by operational data from 50+ projects. If you plan to launch in regions with unstable cellular coverage, a BLE backup becomes critical.
Contact us for a project assessment – we'll help determine the optimal stack and budget. Get a consultation on implementing BLE and telematics today.
Use of Bluetooth Low Energy requires licensing – we assist with the paperwork.