Mbanking is a mobile banking platform built at DMARK Mobile for Ugandan SACCOs (savings and credit cooperatives). It exposes mobile money services — deposits, withdrawals, loans, and fund transfers — to SACCO members via a mobile app, USSD codes, and a web dashboard for monitoring and reporting. Currently serving 30+ SACCOs with 75,000+ monthly transactions.

Proprietary system — no public repository.

The Hard Problem: Every SACCO Runs Different Core Banking Software

SACCOs in Uganda don't share infrastructure. Each one runs a different core banking system with a different data model, different API contracts, and different business rules for things like loan eligibility and account balance calculation. A naïve implementation would couple Mbanking to one core banking system, locking out every SACCO that runs something different.

Hexagonal Architecture as the Solution

Mbanking uses hexagonal (ports and adapters) architecture to decouple the application core from any specific SACCO backend. The domain logic — transaction processing, balance checks, loan workflows — operates against abstract port interfaces. Each SACCO's core banking system gets its own adapter that translates between the port contract and that system's specific API.

Adding support for a new core banking system means writing one new adapter. The domain logic, the mobile API, the USSD handler, and the web dashboard are untouched.

Multiple Entry Points, One Core

Three distinct entry points hit the same domain layer:

• Mobile App API — Django REST Framework, consumed by the SACCO member mobile application built by a separate team. Handles authentication, transaction submission, and balance queries.
• USSD Entry Point — for SACCO members who don't have smartphones or data. A USSD session walks the member through a menu tree to deposit, withdraw, or check balance via a feature phone.
• Web Dashboard — internal interface for SACCO administrators and DMARK operations to monitor transaction volumes, system health, and generate reports.

The USSD path is deliberately simple — it needs to work on the most basic handsets with the least reliable connections, so it is stateless and menu-driven.

Telecom Integration via DmarkPay

All mobile money operations (deposits, withdrawals, transfers) route through DmarkPay — DMARK's internal telecom abstraction layer that wraps both MTN Uganda and Airtel Uganda. Mbanking never speaks to a telecom directly. DmarkPay normalises the differences between the two networks and handles retry logic at the telecom boundary.

Observability

Given that failures involve real money, observability was built in from the start: API request logging, transaction state tracking, SMS gateway health monitoring, and server resource metrics. When a transaction fails, there is a full audit trail from the incoming request to the telecom response.

Built With

Backend: Django, Django REST Framework, PostgreSQL
Infrastructure: Docker, internal CI/CD
Integrations: DmarkPay (MTN Uganda, Airtel Uganda)