Banking Apps With Flutter? The Overview and Opinions

Flutter is more and more often mentioned as one of the technologies suitable for the implementation of large mobile banking projects. Is this technology really ready for such a challenge? Read the opinions on building Flutter banking apps and how the banking industry changes.

• The number of banks that have opted for Flutter in the case of building their mobile banking applications is growing. 
• The possibilities of Flutter and its potential developing year by year are convincing to use this technology even in such complex projects. 
• Specialists from three banks interviewed - Nubank, ING Silesian Bank, and Credit Agricole Bank Polska - rated Flutter as a 9 (out of 10 point scale) when asked how willing they would be to recommend this technology for banking apps.

By reading this article, you can learn about:

• How the banking industry is changing?
• What are the must-have features in banking apps?
• How technology can boost the development of banking apps?
• What role can Flutter play in the transformation of banking?
• What are the opinions about Flutter in banking projects?

You can also find more conclusions from the implementation of a large-scale banking project in our eBook.

How the banking industry is changing?

The banking industry is undergoing the most significant digital transformation in history. In the face of physical bank branches closing down and pressure to increase market share, it is a natural strategy for the banking sector to enable the use of financial services in a completely new way - a digital way. Soon, digital banking will no longer be optional but mandatory to keep up with market needs.

This trend was additionally accelerated by the pandemic, as a result of which, according to a Boston Consulting Group report, as many as 24% of clients wanted to stop visiting physical branches. On top of that, 44% of clients in the 18-34 age group started using online or mobile banking in 2020 for the first time. It shows that a large number of people who use mobile banking apps have joined the market of digital banking in a short period, and it can be assumed that this tendency will be growing. 

For banks, this means facing the challenge of serving many online users simultaneously and introducing the availability of more and more services via mobile banking apps. It will require fast, stable, and modern technology that allows such financial institutions to quickly go through this digital transformation to be able to satisfy end-users.

What features of banking apps become must-haves?

The Digital Banking Maturity 2020 Report states that the pandemic has changed banking and fast-tracked the development of digital channels. On the one hand, 60% of banks have closed or shortened the opening hours of their branches. On the other hand, they have implemented new digital functionalities such as fully remote account opening (34% of banks), remote identification and verification (23%), and contactless payments (18%).

Banks need to fine-tune their online product offerings to serve their customers better. Customer experience is a distinguishing factor affecting customer satisfaction, and in turn, it has a massive impact on a bank's C/I (efficiency ratios) and ROE (return on equity). Moreover, in 2022, banking app users have already gotten used to some digital banking solutions. Features that were innovative a few years ago have become a part of the standard offers of banks.

Some standard features of mobile banking applications are:

• Virtual debit card
• Chatbots with advanced use cases
• Chatbots allowing transactionality
• The fully digital process of account opening
• Making a transfer also transfers using the beneficiary's phone number or *Blik
• Opening a foreign currency account
• Buying insurance or joining the investment fund
• Personal Finance Management
• Spendings predictions
• Budget and transfers notifications
• Measuring financial health
• Benefit club with discount offers
• Applying for a credit card or loan.

*Blik is one of payment systems in Poland that allows users to make instant payments and withdraw cash using only the user's standard mobile banking app. You enter a one-off, 6-digit code BLIK code and confirm the transaction with your PIN in the banking app. 

Moreover, soon Beyond Banking services such as buying parking and transport tickets, paying for motorway access, buying access to airport lounges, company registration, applying for social benefits, and similar services will also play a key role in the value proposition for customers. Subsidiary opportunities can help distinguish innovative banks from traditional ones and be treated as key factors increasing acquisition.

How technology can boost mobile banking app development?

The most frequently mentioned targets by banks are growing the number of customers and increasing customer value. These goals often influence the decision to build a new mobile application. Banks can't compete anymore over the price of their services, so what's left is the good offer and the good product - a banking app. The right mobile technology is required to achieve that. It has a significant impact on the final result. 

Technology can boost mobile banking app development through its efficiency, impact on the speed of the development itself, and alignment with the product's future vision and needs. Also, by enabling easy implementation of features, animations, and UI elements and offering ready-to-use solutions/packages.

What role can Flutter play in banking app transformation?

The most common question regarding Flutter technology is, can Flutter be used for enterprise software development? Such questions are legitimate because you can find a vast number of smaller startup mobile applications written with Flutter. Since official Flutter's launch in 2018, over 400K apps have been released with this technology. Still, until recently, there weren’t many large-scale use cases of Flutter yet. Enterprise apps require more complex features, higher security, and higher performance, and it was not obvious for a long time how Flutter would behave in this environment.

Yet, many examples of Flutter apps have shown that Flutter as technology is one of the leaders in most of the mentioned above aspects. Moreover, the mobile app development with Flutter is faster than in native technologies, which is significant for the banking industry. Banks need to adopt innovations and trends quicker than other sectors to keep up with the constantly changing customers' needs. Flutter technology is a huge time saver in such a case.

To recall conclusions from our earlier article Lessons Learned After Making the First 10 Commercial Apps in Flutter: 

• 90% of Flutter code doesn't need to be written twice for both native platforms, so 90% of the time is saved compared to native applications. It's also a cross-platform technology that simultaneously serves iOS and Android.
• In Flutter, beyond sharing the business logic and user experience within the Design System, it's possible to use plenty of ready-to-go libraries to speed up the development process by providing commonly used logic for many elements used within the app.
• It's easy to integrate Flutter with many important native components such as biometric authentication, security plugins, analytics, etc.
• Flutter projects typically need 8-10% of the time spent on bugs compared to React Native, with 7-14%. 
• Flutter gives excellent opportunities when it comes to implementing animations.

What’s more, large-scale banking app architecture is leveled with separate but interconnected layers such as data access, business, service, or presentation, and it requires transparency to be understandable for different teams. The scalable architecture enables the simultaneous work of several teams (squads) working independently on different business features. The Flutter environment is very efficient in terms of splitting the work between developers while maintaining high efficiency. It also shortens the time to market for such enterprise applications. 

Moreover, in cases where different technology is used for Android and iOS, it may cause inconsistencies in the application design, features, and user experience (ex., different rates in Google Play and App Store). Also, enterprise application developers need to handle many production tickets every day, which delays the implementation of the new features. On top of that, when the code is different for each system, it increases the difficulty of implementing bug fixes and updates. Flutter, as a cross-platform solution, greatly simplifies application management.

To sum up, the role of using Flutter in banking projects can support this industry in fast digital transformation because it has already met all the requirements. The technology has been developed since 2017 and has also reached stability. Flutter technology is also constantly improving and gathers more and more followers because of its many assets. Some banks have already decided to take advantage of it and blaze the trail as technological innovators.

Mobile banking apps with Flutter - Opinions

At LeanCode, we have delivered a mobile banking app with Flutter for Credit Agricole Bank Polska this year and based on this example, we can certify that Flutter is enterprise-ready technology - as we further described in the Building Mobile Bankings Apps with Flutter eBook. However, to show a broader view on using Flutter, we interviewed specialists from three banks that built their mobile banking applications with this technology and asked them about the main risks and benefits of using Flutter as well as what led them to bet on it in such large-scale projects. 

Who we interviewed:

• Reinaldo Moreira da Silva, Engineering Tech Manager at Nubank – “Conta e Cartão” banking app
• Jakub Biliński, Expert Dev Engineer and Chapter Lead at ING Silesian Bank – “ING Business” banking app
• Tomasz Czerwiński, Strategy and Architecture Department Director and Technical Tribe Owner at Credit Agricole Bank Polska – “CA24 Mobile” banking app

Why did you decide to try out Flutter? What other frameworks were considered, and what was the winning argument in favor of Flutter? 

Reinaldo Moreira da Silva (Nubank): 

The main reason to try an alternative language was the pain point of hiring specialized engineers for Android and iOS, it slowed down the development a lot. We’ve tried React Native in some of our major features and Kotlin Native. After exhaustive testing, we’ve found out Flutter is the best option mainly because it has the best tooling experience for the developer, performance, and easiness to ramp up.

Jakub Biliński (ING Silesian Bank):

A few years ago, we wanted to release a completely refactored version of our ING Business mobile application. We were experimenting with multiple technologies. Even though we were skeptical about choosing a framework for the beta version, after developing proof-of-concept in Flutter, we decided to choose it as a tool that fits our needs. We also tried the native and hybrid approaches. Writing two native mobile applications would be too time-consuming for us due to the complexity of our system. The hybrid proof-of-concept was great on many levels, but it didn't offer the same level of "native-fell" as other solutions.

Tomasz Czerwiński (Credit Agricole Bank Polska):

We were looking for a technology to support us in the business context. We also weren’t sure whether we should choose a native or cross-platform solution. However, we had some negative experiences with building an application in native mode. The maintenance costs of our native banking apps were increasing, and they were diverging because of the different platforms. So we started to lean toward cross-platform technologies. At first, we were considering Kotlin, Swift, React Native, and Flutter. We wanted to bet on something innovative that would accelerate our product and strategy development. We decided to do three PoCs with Flutter, and they showed us that Flutter was both an efficient and effective solution.

What were the biggest risks behind Flutter? What were the main obstacles with Flutter which hindered your performance as a team?

Reinaldo Moreira da Silva (Nubank): 

The biggest risk was committing to change all app code into Flutter, and it became deprecated. We had to reach out to the Google team to understand the long-term vision of the project. As a team, the initial struggle had code in multiple languages for one single feature (sometimes, we had to debug a code in JavaScript, Kotlin, Swift, and Flutter at the same time); later, this issue was gone. Also, as it uses an almost unknown language to people, most of the time, the engineers had to ramp up Dart. The good side of this is that Dart is easy to learn, and the ramp-up is fast. Another risk is the company not prioritizing the migration well, but this can be solved with alignment with higher management.

Jakub Biliński (ING Silesian Bank):

The biggest problem was (and, to be honest, still is) major Flutter and Dart changes from version to version. Migrating from version to version was rough in some cases because small parts of our code were not working properly, and some libraries were incompatible. It was not that big of a deal but annoying for sure.

Tomasz Czerwiński (Credit Agricole Bank Polska):

We were analyzing the risks connected with the Flutter market. Was the technology not too young? We were making an important mobile app for our customers to manage their finances. We had to answer the question if the technology is mature enough to do it. When it comes to obstacles, it turned out you can have errors in Flutter - you might think Flutter is instantly seamless, but it’s not. When it comes to clearing and fixing errors but also preparing for a large release to the market, you need a continuous improvement of test processes, and that was a discovery for us.

What are the benefits of using Flutter? How has Flutter helped you reach your business goals?

Reinaldo Moreira da Silva (Nubank): 

Many benefits: an excellent toolkit for the developer, build time extremely fast, fast language ramp-up, multi-platform. We were able to launch features surprisingly fast. Also, it aligns very well with server-driven content. Many of our OKRs were delivered in time only because of Flutter.

Jakub Biliński (ING Silesian Bank):

Flutter helped us reach our goals. With Flutter technology, we can deliver new features faster and better than before. It may sound so cliche, but working on a  codebase that's mostly shared is a blessing. Especially when we have to fix something, and this change will fix the problem on both operating systems. That way, we can help our clients faster.

Tomasz Czerwiński (Credit Agricole Bank Polska):

I had an impression that it was either Flutter technology or people who came to work on this project, but we could start the development in just 3 weeks after building a team. Also, Flutter made coding functionalities easier to implement. You don't have to create the code for each operating system and test the functionalities on each of them separately. Another benefit is that Flutter helped us to achieve that fantastic, seamless customer experience. In the end, users should not be able to spot the difference in how something is implemented, no matter which platform they use.

How much are you willing to recommend Flutter to other Mobile Developers or stakeholders in the banking industry? (1 - not at all, 10 - highly recommended).

Reinaldo Moreira da Silva (Nubank):

Today, I would rate Flutter as 9 out of 10, but considering all points above and what the other frameworks have to offer, Flutter is the best in the market today for fast growth.

Jakub Biliński (ING Silesian Bank):

I would give Flutter a strong 9.

Tomasz Czerwiński (Credit Agricole Bank Polska):

I think we chose the best technology for our case, and from a time perspective, I can say we’re happy about this decision. Flutter gives us a lot of possibilities for further app development and its functionalities. I would rate Flutter as 9.

Flutter in banking apps: Summing up

Based on all the above, we can drive the conclusion that using Flutter mobile app development for banking is a great solution, and its effectiveness has been proven. Flutter ensures the quick addition of new functions in the app and the ease of maintaining the entire application. Flutter technology is also known for its seamless UI/UX features and robust design elements, which allow for delivering a unique customer experience.

If you want to find out more on lessons learned from delivering the Credit Agricole project or you're wondering whether building a Flutter banking app may be the right solution for you - download the Building Mobile Bankings Apps with Flutter eBook.