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Energy consumption management system

Learn how we developed a GDPR-compliant software solution for keeping consumers informed of their power demand and educating them on smart energy consumption.

Period of collaboration:
May 2020 – July 2021
Berlin, Germany

About the client

Homee GmbH is a Germany-based company that provides solutions for automating the work of domestic smart Wi-Fi devices. In 2020, the company launched a renewable energy business unit called stromee. stromee is focused on providing renewable energy services to consumers. Our client needed high-class software that would automate tasks for end users and encourage them to be conscious of their energy consumption.

Development goals

The energy supply industry in Germany is represented by a large number of electricity providers, and new providers are regularly emerging. Our client had to present a product that would stand out with its unique benefits, demonstrate its capacity for contributing to conscious energy consumption, and quickly claim its market share.

One of the client`s priorities was creating a holistic mobile application that would encourage people to monitor their energy consumption and contribute to economical electricity use.

Our client set the following objectives:

  • Create web and mobile applications with features for forecasting, monitoring, and controlling energy consumption, facilitating contract management, and entering meter readings

  • Design a user-friendly and engaging interface to provide users with a comfortable and educational environment that would strengthen their enthusiasm for rational electricity use

  • Ensure proper compliance with GDPR requirements for security and technology

  • Automate the process of creating a contract with a new electricity service provider

  • Attract users through valuable content and actionable tips on saving energy resources that they can apply in real life to gradually reduce their electricity consumption

This project relates to the highly specialized renewable energy supply industry in Germany. We carried out thorough research into country-specific requirements regarding energy consumption and the needs of the target audience before starting development.


Web application

A website was initially considered the starting point for users to get acquainted with the client’s company. That’s why our main focus was designing a simple yet useful landing page that would include educational content on conscious energy consumption to demonstrate the benefits of stromee.

The web application presents basic features for customers to calculate their consumption and start working with stromee:

Consumption calculator

Potential users can calculate their tariffs on the website by entering basic information such as their zip code, residential address (optional), number of home occupants, and the previous year’s energy consumption. After seeing the calculation results, users can proceed with creating a contract.

Contract creation

Following a simplified flow, users can quickly create a contract with stromee. Core functionality is then available in the mobile application.

Educational content

Users and website visitors can enjoy helpful materials on conscious energy consumption on the blog and explore energy saving tips. For those who would like to learn how the stromee mobile application works, there is an FAQ section.

Mobile application

The mobile application presents core functionality. We implemented all of the features users would need to analyze their energy consumption. We also facilitated the process of entering meter readings into the system, managing contracts, and getting personalized tips on efficient energy use.

At the client’s request, we came up with the following pack of features:

Monthly and yearly consumption forecasts

These forecasts help users see their current and potential energy use and conduct an energy consumption analysis. The system builds an interactive and dynamic consumption chart based on entered meter readings and seasonal consumption trends. Users have access to monthly and yearly consumption forecasts with a detailed overview of energy consumption.

Contract creation

We designed two methods for creating contracts. The first is a four-step procedure that involves entering personal and financial data, revealing the reason for choosing stromee, and giving information on the previous electricity provider. The second method uses a simplified flow: a user has to enter only personal data and upload old invoices.

Contract management

Users can see their contract details, including all previously entered meter readings along with tariff and billing details, and can track the status of their contract.

Management of multiple contracts

The team implemented this feature for people who own several apartments or houses, allowing them to manage all their contracts under one account.

Meter readings

The application contains a history of meter readings entered by the account owner and by inspectors. Once a meter reading is entered, the data is synchronized with and stored in the PowerCloud system.

Educational content

Users can explore energy saving tips and read the FAQ section right inside the application.

Promo codes

The client frequently holds special events with promo codes. Users can enter them when creating a contract to get a discount.

Live chat support

We integrated with FreshChat for users to be able to ask for help and quickly get answers to their questions.

GDPR compliance

This software must comply with strict GDPR requirements on the protection of users’ personal data. We made sure to inform users of each piece of personal data the system uses and when, indicating the length of time for which the data will be kept and assuring its full confidentiality and protection. During product development, the Yalantis team did not have any access to users’ personal data.

Challenges and solutions

Forecasting users’ energy consumption

One of the biggest challenges was creating a means of forecasting users’ energy consumption, as this is one of the unique benefits our client offers and is the application’s core functionality. Our analysts came up with a dynamic formula that uses the average energy consumption in Germany by region and seasonal trends to make approximate forecasts. As users enter new data on their energy consumption, the formula reflects it and dynamically adjusts to present more precise figures.

Integration with PowerCloud

We integrated with PowerCloud to maintain data transmission and storage. PowerCloud is the only service in Germany that works with utility contracts, meter reading input, tariff calculations, and invoicing.

This integration was quite a challenge because of the service complexity. We faced:

Unclear documentation

Figuring out how the service operates and how we could build a reliable application based on it was our primary task. We held several workshops with PowerCloud specialists to look into the service’s peculiarities and adjust the functionality development process accordingly.

Poorly configured events

The PowerCloud event system uses HTTP requests, which decelerate the transfer of data. We built the application’s functionality by tailoring it to PowerCloud requirements and presenting users with a convenient product.

Mismatched data from APIs

PowerCloud uses the SOAP API and REST API to exchange and transfer data. To make the application present accurate tariff information to users, for example, we had to use both of these APIs. However, our requests returned conflicting data. Our developers and quality assurance specialists experimented with requests using a trial-and-error method to get matching data from both APIs and configure the correct work of endpoints.

Solution architecture

We built this solution architecture considering the following requirements:

  • Proper server maintenance for smooth system operation

  • Load balancing in the event of a rapid traffic increase

  • Secure transfer of personal data from PowerCloud database to the stromee database


One of our main priorities was creating a user-friendly and simple interface. To make stromee visually attractive right from the beginning, the team:

  • Designed attractive applications with neutral and appealing colors and handmade illustrations that reflect the spirit of stromee

  • Filled the mobile application with essential functionality while maximizing simplicity in use and ensuring intuitive navigation

  • Implemented animated elements, charts, and tables to visualize users’ consumption tendencies and make it entertaining and engaging for users to monitor their power demands

Thanks to the client, we always had user feedback to listen to and rely on during development. End users helped us create a barrier-free environment with simple and entertaining workflows.

Time constraints

We had to quickly present the application’s unique value and benefits to users to help the client win market share. The Yalantis team applied an iterative development model, which helped us swiftly analyze users’ reactions to the product and its functionality. We considered users’ feedback between releases and acted on it when making application updates. To achieve such a fast pace, we had to adjust the development process to the time limits.

To meet strict deadlines, we:

Went for a two-track development process

This meant the parallel creation of web and mobile applications, which accelerated development and helped us deliver ready-to-use web and mobile applications at the first release.

Used appropriate technologies

Developers applied the CI/CD method to accelerate product delivery to the server and used AWS Elastic Beanstalk to conveniently manage the backend infrastructure and services.

Ensured efficiency from the get-go

We were able to present the client with the projected cost of the application’s MVP version and approve it on the tenth day of the kick-off stage. The quick start of the development process helped us demonstrate the first screens of the application already in the first demo session. The client was able to assess and try a real product in a short amount of time.

We held regular meetings with the client’s stakeholders where we planned releases, planned pre- and post-release activities, and allocated responsibilities among team members. This helped us set up well-organized work processes and achieve maximum productivity.



Ensured a large influx of users

Thanks to our coordinated work with the client, we were able to reach the client’s initial goal for the number of clients far before the end of the year — and even exceed it.


Meet strict deadlines

We managed to work under strict time constraints, delivering the product in a series of regular releases. The team fixed user experience inconveniences quickly and adjusted to users’ needs based on constant feedback. This approach helped us deliver a final product fast and produce a solution that fully meets the audience’s needs.


Adopted new management practices

Our close cooperation with the client brought benefits not only to the product. Our client also decided to adopt some of our management practices, appreciating the efficiency of the methods we used during work on the project.

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