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Andreja Zubac
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Mobile app

Pošta Srbije

The mobile app of Serbia's national postal operator, built in Jetpack Compose with an existing XML wallet integrated through interoperability.

Company
Abstract
Timeline
2022 – 2024
Platforms
Android
Stack
  • Kotlin
  • Jetpack Compose
  • Android Views (XML)
  • Compose interoperability
  • Clean Architecture
  • Biometrics
  • Google Maps
Three Pošta Srbije screens: quick postal services, the wallet and the post office map

Overview

The official mobile app of Pošta Srbije gives customers quick access to postal services: sending Post Express shipments, tracking parcels, calculating prices, finding post offices and managing a wallet for payments.

My role

Android Engineer at Abstract. I built the new app and integrated the existing transactions and wallet module into it.

The challenge

The product came from two separate codebases. A new app had to be built on Pošta's existing backend, while transactions and the wallet already lived in a separate, older project written with classic Android XML views. The two had to become one app without rewriting the wallet from scratch.

The solution

I created a new Jetpack Compose project on top of the existing backend. Then I brought in the XML transactions and wallet project as components, using Jetpack Compose interoperability as a layer that loads the View-based screens inside the Compose UI. The proven wallet flows kept working while the rest of the app moved to a modern, Compose-based architecture.

Architecture & implementation

  • Compose–View interoperability layer hosting an existing XML-based module.
  • Legacy-to-modern migration onto the existing backend.
  • Map clustering with marker aggregation for post office locations.
  • Clean Architecture (DDD).

Key features

  • Quick postal services: Post Express, invitations, account, tracking, ePhilately and more
  • Wallet and transactions
  • Biometric authentication
  • Post office map with clustered markers
  • Price calculator for domestic and international shipments
  • Registration and sign-in

Screenshots

Home screen with a grid of quick postal services
Wallet screen prompting the user to register
Map of Belgrade with clustered post office markers and location details
Price calculator form for domestic shipments
Registration form for personal details

Results

  • Published on Google Play, where it has more than 100,000 downloads.