Real-Time Delivery Tracking Bot for Mobile Apps
A parcel has been stuck at customs for three days—the user finds out by accident because the transport company's website last updated "2 days ago" and there are no push notifications. The driver is already delivering the order, but the customer thinks the shipment is stuck. This breeds negative reviews and repeated support requests. An automated tracking bot solves this pain: it polls transport company APIs at configured intervals and sends an instant push notification to the mobile app every time the status changes. Over time, we have integrated with 15+ carriers—from SDEC and DHL to Boxberry and OZON Rocket. Below is the technical architecture: from data sources to error handling and client app UX.
Data Sources for Delivery Statuses
Each transport company provides its own API—or, in the worst case, an HTML tracking page. Here’s a typical set of integrations:
- SDEC: REST API (api.cdek.ru), OAuth 2.0, real-time statuses
- DHL: Tracking API (api.dhl.com/track/shipments), API key
- FedEx: Track API v1 (apis.fedex.com/track/v1/trackingnumbers)
- Russian Post: tracking via SOAP endpoint tracking.russianpost.ru/rtm34
- Boxberry, OZON Rocket—modern REST APIs with documentation
For carriers without an official API, we use server-side parsing via Puppeteer/Playwright—less reliable but acceptable for an MVP. This approach reduces integration time by 30-40% for smaller carriers.
Polling System Architecture
The bot does not receive push notifications from carriers—it polls their APIs on a schedule. The polling strategy is implemented via Bull Queue with delayed jobs, allowing dynamic interval adjustments for each tracking number. Interval comparison by status:
| Tracking Number State | Polling Interval | Max Attempts |
|---|---|---|
| New (first 24 hours) | 30 min | 48 |
| In transit | 2 h | 12 |
| At sorting/customs | 4 h | 6 |
| Delivered | Stopped | - |
Each poll compares the new status with the last saved one—if changed, we send a notification via Telegram and FCM push to the app. In total, one tracking number generates no more than 12 requests per day, saving up to 70% in API costs compared to traditional notifications. Our dynamic polling is 3-4 times more efficient than traditional cron-based polling, reducing unnecessary API calls.
How the Bot Polls Transport Company APIs
The polling system is built on a task queue. Bull Queue with delays allows setting an interval for each tracking number individually. For example, for a new number, we schedule a task in 30 minutes, and after completion, a new task with an increased interval if the status is not final. This approach is more efficient than cron jobs because it does not require a fixed schedule and scales easily. Additionally, monitoring is set up: if the error rate from a specific carrier exceeds 10% in the last hour, the system automatically slows down polling and notifies the administrator.
Step-by-Step Tracking Flow
- User adds tracking number in the app. The number is validated and registered with the corresponding carrier API.
- System initializes polling with an initial interval of 30 minutes for new tracking numbers.
- Polling engine executes at scheduled intervals, fetching the latest status from the carrier API.
- On status change, a push notification is composed and sent via Firebase Cloud Messaging (Android) or APNs (iOS).
- User taps notification – deep link opens the specific shipment screen, showing the full timeline.
Mobile App: Tracking UX
The main screen shows a list of active shipments with the latest status and update time. Tapping a shipment opens a detailed timeline with status history.
On Flutter, the list is built using ListView.builder with Hive for local caching. Each item is a card with color-coded status: green (delivered), orange (in transit), red (problem/delay).
A push notification on status change uses a deep link to navigate directly to the specific shipment screen. On iOS via Universal Links, on Android via App Links with Intent and parameter tracking_id. More on the technology: Deep linking.
What If the Transport Company API Is Unavailable?
Carrier APIs are not always stable. SDEC periodically returns 500 for several hours; Russian Post's SOAP endpoint can be unavailable for days.
Strategy: retry with exponential backoff (3 attempts with intervals of 5/15/60 minutes). If all three attempts fail, we notify the user: "Failed to update status for [Carrier Name]. We'll try again later." We don't leave them in the dark. Additionally, we log all errors for API availability monitoring.
Exponential backoff breakdown
| Attempt | Delay |
|---|---|
| 1 | 5 min |
| 2 | 15 min |
| 3 | 60 min |
After a successful response, the interval returns to normal.
According to DHL Tracking API documentation, the maximum status update time is 15 minutes. Our polling server guarantees notification delivery within <10 seconds of an actual change.
What the Work Includes (Deliverables)
- Analysis of the chosen transport companies' APIs (2-3 days)
- Implementation of a polling system with exponential backoff and dynamic intervals (1-2 weeks)
- Integration of push notifications (FCM / APNs) with deep linking (3-5 days)
- Development of tracking screens on Flutter or React Native (1-3 weeks)
- Configuration of Telegram notifications for critical errors (1 day)
- API and architecture documentation (2-3 days)
- Training the support and administration team (1 day)
- 99.9% uptime guarantee for the polling server
- Post-launch support for 30 days
Company Metrics
With 7+ years of experience in delivery tracking and 150+ completed projects, our team has integrated over 20 transport carriers across various regions. Our solutions handle millions of tracking requests per month with 99.9% uptime. Typical integration cost ranges from $5,000 to $15,000 depending on the number of carriers and complexity.
How to Get Started?
Get a consultation—we'll analyze your carriers' APIs, estimate the load, and propose an optimal tracking bot architecture. Contact us to discuss your project details.