Digital-bank Mobile App Development Case Study


The client is the top telecom network operator in Vietnam. This mobile application offers added services to the existing subscribers, allowing them to use their registered personal phones to make transactions with multiple banks. It is one of the first apps that allows one account to connect to several banks. It currently has more than 3 million users, an average of 10.3 million transactions monthly, with a rating of 4.3 out of 5 on the Google Play Store. 

Key Features

  • Transfer money by phone number to 40 domestic banks in Vietnam
  • Allow customers to open savings accounts on mobile phones 
  • Payment for electricity bills, internet, cable TV, etc.

Technical Stacks

  • Native Apps in Apple App Store and Google Play Store
  • JBOSS/EJB3 for web-service and business logic
  • Hibernate for persistence layer
  • Database Oracle 12
  • SOAP protocol for communication between client’s server and external system integration
  • Source management using Bitbucket

Project Overview

  • 1 Scrum team (12 people)
  • 14 sprints to GO-LIVE
  • Development: 7 months
  • Market: Vietnam


The client came to us when they wanted to make a mobile app to integrate their existing banking service system with one of the top banks in Vietnam. Their goal is to enable customers to make bank transactions on any mobile device, anytime, anywhere. 

This is made possible with the mobile app by connecting the existing banks’ system with the client’s telecommunications network. Customers can make transactions through bank accounts, mobile numbers or any of the client’s transaction points. 


When we first started out on this project, there were a large number of concurrent users on the existing network. Our challenge was to create this app and seamlessly integrate it onto the network, without causing any disruption to the existing services. 

On the other hand, we also needed to map out different types of banking operations that need to be connected to the application. Then coding it and integrating it with the telecom network system.


To solve the challenges, we first sit down with the team from the telco provider and the bank to define the requirements for the integration system. We had to understand and analyse the bank’s complex operation processes to develop functions for the app. 

When building the API gateway, we had managed the bank system’s requests and responses from multiple entry points. Then we bring them through a single gateway back to the telecom network system to ensure consistent communication. 

We deployed the system on different nodes on the back end to ensure weight distribution for the platform. At the same time, we had to follow strict security guidelines as there was a lot of customer data that needed to be processed. 


Since its launch, the app is considered a leading player in the Vietnam Fintech scene. It now partners with 12 prominent banks, making it accessible for many more users. It also won two national awards and two international awards in the Finance-Technology industry for its innovativeness and connectivity. 

Looking for a multibanking expert?

1. GEM Corporation is an IT Outsourcing company experienced in developing digital-bank mobile applications. We have worked on developing digital-bank solutions for the top telco provider in Vietnam. 

2. Our domain expertise includes Finance, Banking, and Insurance. We have worked with top consulting firms in the finance industry, developing various applications for banks and insurance companies. 

3. We have more than 9 years of experience. Our offices are based in Hanoi, Vietnam, and Tokyo, Japan.

4. We have successfully built more than 100 successful projects for our clients in the US, UK, Europe, Japan, Korea, Singapore, and many more.

5. Let us know how we can help you build your banking solution. Contact us now and get a quote for your project.