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IT development partner to Germany’s most popular mobile network operator

Co-creation as a success factor. Agility and innovation since 2008. Innovative thinking. Disruptive technologies. Agile methods. Close collaboration. Satisfied retail customers. As an IT development partner, AOE has supported the success of congstar, one of Germany’s most popular mobile network operators and the leading second brand from Deutsche Telekom, since 2008.

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Short time-to-market for new features

thanks to microservice architecture and agility

Outstanding customer satisfaction

thanks to customer self-care and personalization

Consulting and implementation at eye level

thanks to years of understanding the business case

Of course, a lot has happened since beginning this strategic partnership in 2008 – both in the telco market 
in general and in terms of technology, which was reflected repeatedly at different levels of the project. 
To better meet current requirements, the architecture of the e-commerce and sales solution was 
converted from monolith to microservices, for example, and the organization and structure of the 
development teams were adapted. What remained constant: the agile collaboration as equals, the satisfaction of congstar’s customers 
(the trade magazine connect recently recognized congstar as “mobile provider of the year” for the 
eleventh year running), and the aspiration to always tailor products, solutions, and features to the 
needs of the users. congstar and AOE have always been a perfect match when it comes to their methods 
and company cultures. The result is a collaboration in which both sides have the necessary grasp of the brand and its business objectives to scrutinize future ideas and approaches critically – and tackle future challenges ideally with combined expertise.


In light of the technical possibilities, changing customer behavior, and permanent competitive pressures in aggressive market, congstar’s products and the underlying infrastructure require continual adaptation. One of the greatest challenges here is to get new products to the market quickly, despite the complex background processes, while continuing to provide an outstanding user experience and optimal customer self-care options.

Therefore, the technology solution not only had to integrate all the systems relevant for the customer-facing channels, but also the apps and distribution partners’ systems, for example. As the scope of the solution grew, the requirements of the structure and extent of the involved teams also increased, making the project even more complex. As a subsidiary of Deutsche Telekom, congstar also has to manage a balancing act and achieve compatibility between its own innovation-driven aspirations and the historically evolved, 
safety-focused – and thus more cautious – rules of its parent company.


To guarantee the required flexibility and speed, the solution was converted to a microservice architecture. This enabled the teams 
to work independently and get new features online much more quickly (or modify them) as isolated microservices.

Agile work was another prerequisite for enabling innovation-driven action. AOE supported congstar in using agile methods from the beginning: The mobile provider was one of the earliest agile projects in Germany and continues to consistently use an iterative method with MVP (minimum viable product) to this day. This early go-live approach makes it possible to test new functions or products directly with customers and improve the user experience continually, as confirmed by A/B tests and ongoing analyses of user behavior (through customer journey analytics, for example). Personalization at multiple levels (such as personalized offers) gives customer satisfaction an additional boost.

Thanks to this long-standing partnership, AOE has far more relevant expertise than is usual for a strictly development partner: The collaboration has fostered deep understanding of the customer’s business case. As such, AOE is involved in processes and product development at a very early stage and brings historical knowledge 
of the background of developments to the table, in addition to technological and methodological expertise. When necessary, for example, we brainstorm to find creative ways 
of fulfilling Deutsche Telekom’s group requirements in the solution without losing speed or the power to innovate – for example, 
by automating complex documentation processes.

What our customers say

Management summary

Co-Creation since 2008: congstar and AOE have repeatedly adapted the e-commerce and distribution platform to the latest requirements of the saturated telco market.

Thanks to the microservice architecture and agile working methods, new features can 
go live quickly, contributing to high long-term customer satisfaction. This was confirmed by the repeated award as “mobile provider of the year” from the trade magazine connect. Aside from the customer-facing channels (online shop and customer self-care area), 
the solution also integrates the systems for distribution partners and apps. AOE has supported the mobile provider from the beginning with establishing agile methods and implementing innovations. The result is a future-oriented, scalable, cloud-based platform and trusted collaboration at eye level.

Business benefits

Platform solution for online shop, customer self-care, and distribution partners

Speed and flexibility through agile structures and conversion to a microservice architecture

Customer-centricity thanks to optimized customer self-care portal and personalization