Business banking app

Thinslices' Journey with Penta in the European Fintech Landscape

Based in Berlin, Penta started its journey in 2017, and has been Germany's leading provider of digital financial management for SMEs, self-employed and freelancers. The end goal of Penta was to create an integrated digital banking platform that brings together the best of financial services integrations, so that their users can effectively manage all their business activities from the same application. Starting from simple payments to accounting activities and credit management, Penta’s end-users have benefited from features like: expense management and international payments, direct debits and batch payments, customized user management and Visa cards, integration with the desired accounting software.

Being one of the most significant up and running German fintechs with more than 50k users, Penta was acquired by Qonto in July 2022. The two market leaders aim to generate added value for their customers through further innovation in their products and services within the European market, especially in Germany, France, Italy and Spain.

Thinslices started its collaboration with Penta back in 2020, in the middle of the pandemic, when Penta reached out to us to help them build the mobile version for their digital banking application.


The challenge

How can we build a mobile banking app that would be in parity with the existing web version and give users a sleek and easily accessible platform for everyday use, in a short period of time?

Our approach

Penta’s goal was to develop a mobile app that would complement their existing web platform whilst hitting tight deadlines for market release. After defining the scope, ways of working and the desired product roadmap, we’ve rapidly put together a team of 7 engineers, one UX/UIdesigner and a product manager who were able to quickly start the onboarding process and jump straight into delivery.


For nearly 16 months, our team’s main focus was to bring a mobile app to parity with the web version, in order to allow Penta's new and existing users to enjoy from the comfort of their smartphone, the majority of features already existent on the web platform.

Following a first, major and successful release of onboarding new users (sole proprietors and freelancers) in Jan 2021, our team has worked together with Penta to define the next steps of the product roadmap. We’ve started working to add Sub-Accounts and Permissions features to the mobile app, which facilitated users to organize their business finances under a single account. This second phase of the project was completed before the end of 2021.

During the entire collaboration with Penta, the Thinslices team worked mostly autonomously on all the tasks. We have rapidly integrated with Penta’s product development process, and always strived to deliver on the immediate needs whilst identifying key blockers. Our best practices and delivery methodologies have been recognised and appreciated within Penta’s teams, which led to an ongoing successful and trustworthy partnership.

Post the acquisition by Qonto, our team was asked by Penta to help with the migration of all of their users towards Qonto, and help with the sun setting of the platform, which is scheduled to be completed by the end of 2023.


Technical specifications

React Native, ObjectiveC/Swift, Java/Kotlin
Google FCM & Big Query
Bitrise & Fastlane for deployment
& Sentry for issues tracking
AppsFlyer & Snowplow integrations for marketing and data teams

Delivery process

In our collaboration with Penta, we adopted a strategic approach to project management, aligning our quarterly objectives with the overarching goals of the company. This alignment ensured that our sprint priorities were clear, facilitating focused and efficient feature development. The adoption of best practices such as Think Debate Code, Pair Programming, and Feature Peer Review, practiced with high discipline, significantly boosted our productivity and development velocity.

Excessive meetings are a well-recognized challenge within the tech industry. To mitigate this, we took proactive steps to streamline our meetings by rotating facilitation duties, setting clear agendas in advance, and keeping a strict eye on time.

These strategic and operational optimizations contributed to the transformation of the Penta Mobile team into a high-performing unit. The team's disciplined application of best practices and efficient project management enabled us to rapidly deliver a suite of valuable features, including an onboarding flow, Apple Pay integration, subaccounts, and a referral flow. The impact of these features on Penta's service offering was significant, demonstrating our ability to deliver complex solutions within tight timelines.

At the heart of our delivery process was a commitment to continuous improvement, guided by frequent communication, the setting of clear quarterly objectives, and adherence to a rigorously defined set of delivery KPIs. This framework allowed us to swiftly identify and address pain points, optimizing our development cycle for speed and responsiveness. We set ambitious targets for our KPIs, such as aiming for 0% blocked days to ensure an uninterrupted workflow, and striving for 0% delayed days to maintain our sprint schedules. These targets were instrumental in fostering an agile and efficient development environment.


Our dedication to process efficiency was further evidenced by our focus on key metrics such as the average time required for testing and closing features, with a goal of 0.5 to 1 day depending on complexity. This emphasis on rapid turnaround times, combined with a target of 2 hours for average merge request (MR) closing times, underscored our commitment to maintaining momentum in development without compromising on quality. Additionally, by aiming for an average of 6 story points (SP) per developer per sprint, we not only quantified individual contributions but also ensured consistent progress towards our development milestones.

This structured and disciplined approach to our delivery process played a pivotal role in the successful outcomes of our partnership with Penta. By rigorously adhering to our KPIs and objectives, we not only met but often surpassed project expectations, illustrating the effectiveness of structured project management methodologies in achieving outstanding results in software development.



0 Blocked days

% Blocked days = percentage of days, in a sprint, when a feature delivery was blocked.

0 Delayed days

% Delayed day = percentage of days, in a sprint, when a feature delivery was delayed.

0.5 - 1 day test days

AVG Days to test and close = days required for sign-off and ship. (depending on the complexity)

2h MR closing time

AVG MR closing time = number of hours required for review and merge with common code.

6SP per developer

AVG SP per developer = average number of story points delivered per developer per sprint.
What others say

We excel at what we do.
Take our happy clients’ word for it.

VP Engineering,
penta 1

"Their delivery is always satisfactory, and their communication is timely, open, clear, and on eye level."



In our collaboration with Penta, we set out to make the transition from web to mobile seamless and impactful. By integrating complex features from the web app into the mobile environment, we successfully onboarded over 2,000 users across iOS and Android platforms, a clear indicator of the app's appeal and functionality. The smooth integration with Apple Pay further highlighted our dedication to enhancing user convenience and security, reinforcing the app's value proposition. Our ongoing commitment to support and improve mobile features reflects our adaptable, user-focused approach, ensuring that the app remains relevant and efficient.


2k +

mobile users on boarded across iOS & Android


OKRs accomplished


Android customer ratings (Increased from 3.9)


iOS customer ratings (Increased from 3.7)

The recognition of the Thinslices team as knowledgeable and experienced by Penta is a testament to our meticulous work and the seamless migration process we engineered. By achieving zero CRM tickets per week and implementing push notifications, we've not only maintained a flawless operational standard but also significantly improved customer outreach and engagement. These technical achievements underscore our team's capability to handle complex challenges with finesse and precision.

Expanding on these technical accomplishments, our partnership with Penta has also yielded impressive business outcomes. The banking platforms have seen a surge in user engagement, with over 40,000 customers now leveraging Penta’s offerings. This growth includes an uptick in paying customers, indicating not just wider adoption but also deeper trust and reliance on the platform. Our efforts have contributed to an enhanced user experience, as reflected in the significant improvement of mobile customer ratings, jumping to 4.5 on Android and 4.7 on iOS. These ratings are more than numbers; they represent user satisfaction and confidence in the platform.



Furthermore, Penta's increased popularity in Germany speaks volumes about the platform's stability, scalability, and user-friendliness. The role of Thinslices in this trajectory has been to ensure that Penta's web and mobile banking platforms not only meet but exceed the modern user's expectations for secure and easy-to-use online banking. Our work together has positioned Penta as a leading choice for digital banking solutions, demonstrating the power of thoughtful, user-centric software development in driving business growth and customer satisfaction. This partnership has shown that with the right expertise, technology can transform businesses and enrich user experiences in profound ways.


 Teams as a Service (TaaS) 

Our work

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