Makes complex applications easy to use with intuitive user interfaces.
A good user interface helps users find their way around quickly and translates complex requirements into a visual design that is easy to understand and intuitive to use. In UI design, content is clearly structured, functions are arranged in a logical manner, and interactions are designed so that users can complete their tasks efficiently.
User interface design is a component of user experience design and refers to the specific layout of the interface. This includes visual elements, interactions, and the hierarchy and arrangement of content, all of which significantly influence the user experience.
We design user interfaces that provide clear guidance even in complex applications. Visual design, clear hierarchies, and well-thought-out interactions work together in our UI design to reduce confusion by guiding the user’s gaze and highlighting relevant content.
Depending on the application, different types of interfaces are used, such as graphical user interfaces, voice-based interfaces, or HMIs in industrial settings. We help identify the right solution for each specific use case and user.
UI design is an integral part of our UX work and is closely integrated with software development. This allows us to create user interfaces that fit seamlessly into existing systems, can be further developed, and function reliably in their intended context.
Interested? Then you'll find all the information you need about user interface design with slashwhy on this page.
Your advantages
The success of a digital product is determined by how it performs in everyday use. If users can’t find their way around quickly, it leads to errors, frustration, and unnecessary effort—even with technically sophisticated applications.
With a well-designed user interface, we create clarity. We structure content, make functions understandable, and ensure that interactions are intuitive and reliable. Especially with complex systems, a clear visual design with a logical hierarchy helps provide orientation and avoid confusion.
This has a direct impact on your product quality: processes become more efficient, usability increases, and the user experience becomes consistent—regardless of the device or usage context in which the application is used. For us, UI design is therefore not an optional step, but a central component of product development.
A good user interface ensures that users can quickly find their way around and complete tasks efficiently. To achieve this, we combine clear structures with intuitive interaction options and a cohesive visual design that is precisely tailored to the specific use case.
When users hesitate, make mistakes, or can’t find features, it’s often because of the interface. Unclear structures or a lack of feedback quickly lead to frustration and inefficient use. To prevent this from happening in the first place, we integrate UI design, user research, and UX testing from the very beginning. This allows us to understand what users really need and design interfaces that feel clear, intuitive, and cohesive.
We develop user interfaces step by step, consistently focusing on the context of use, requirements, and the users’ tasks. First, we organize content and functions into a clear structure and define the most important interactions. Building on this foundation, we create the visual design and translate it into a consistent system of components and rules. The result is a UI design that is intuitive, implementable, and scalable for the long term.
Design systems ensure consistency and save time during development. They help ensure that recurring elements are designed consistently and that new features are integrated more quickly.
That depends heavily on the use case. We don’t choose the right type of interface based on trends, but rather on what works best for your users. Working closely with our user research teams, we use methodological approaches to determine which interface types are best suited to your specific use case and provide concrete recommendations.
Great user interfaces come to life when all our UX disciplines work together seamlessly. User research lays the foundation, prototyping makes ideas tangible and measurable, and UX testing brings in real-world feedback. In UI design, we turn all of this into a clear and intuitive interface that users can easily understand and use.
Alexander Trienen
Senior UX Designer at slashwhy
In user interface design, we balance usability engineering with aesthetic design and accessibility. I see accessibility as a natural part of the development process. It takes some effort and a willingness to learn, especially at the beginning, but it gets easier over time and pays off through greater reach, increased revenue, and more satisfied users.
Winona Biber
Senior UX Designer at slashwhy
I like to use the “knife metaphor” to illustrate user-centered design: the product we build, with all its features, might look like a Swiss Army knife with countless functions, but our users were really just looking for a simple bread knife.
Jan Kuhlmann
UX & UI Designer at slashwhy
Our approach
A good user interface evolves step by step. To get there, we work together to analyze the context of use, requirements, and technical constraints. The result is an interface that fits the product, the specific situation, and the tasks users want to accomplish.
Step 1 | Understanding the context of use and the requirements
The first step is to clearly understand the context in which your product will be used. What tasks should users accomplish with the interface? In which environment will it be used, in an app, on a machine, or as part of a digital service? And which design or technical foundations are already in place, such as an existing brand or product design? These questions help us align content, structure, and visual design from the very beginning.
Step 2 | Developing structure and visual hierarchy
In the next step, we structure content and features in a clear and intuitive way. We prioritize information, define interaction flows, and bring first ideas to life in wireframes. This creates a strong foundation for the final design.
Step 3 | Designing and developing the interface
Now we shape the visual design. We define typography, colors, spacing, and design elements, and bring them together into a cohesive look and feel. The interface is designed across different devices so it works reliably in a wide range of usage scenarios.
Step 4 | Transforming design into a workable System
A good UI goes beyond individual screens. We turn the design into a consistent system of components, rules, and states. Design systems create a shared foundation for design and development, making it easier to build interfaces consistently and evolve them in a structured way.
We design detailed user interfaces with clearly defined screens and states. They show how content is structured, how features are accessed, and how users are guided through an application.
You get a clear visual foundation that everyone involved in the project can rely on, from business stakeholders to developers.
We build design systems and reusable UI components for scalable products. We define visual guidelines such as colors, typography, and states, and make sure your interfaces stay consistent across devices and use cases.
On this foundation, we continue to grow your application together. We implement new features efficiently, create clear communication within the team, and ensure your product evolves in a structured way without starting from scratch each time.
We provide clear design specifications for development. They include detailed information on layouts, spacing, states, and interactions, along with all relevant assets for implementation.
For your project, this means less back and forth between design and development, fewer ambiguities, and a much higher quality in how the user interface is implemented.
And we go one step further. As a comprehensive development partner, we guide you through the design process and take care of the technical implementation of your application. From the initial idea to the finished product, you have one team at your side.
We define clear requirements for accessible and inclusive user interfaces. This includes aspects like contrast ratios, readability, focus states, and intuitive interactions.
This ensures your application works well for diverse user groups and meets established standards such as the WCAG guidelines, which is a key factor for quality, reach, and often regulatory compliance.
Depending on the project, we create additional deliverables such as icon sets, animations, microinteractions, or design tokens to support the technical implementation of the design.
The exact deliverables depend on your product, the context of use, and the maturity of your application. This way, you get exactly what helps move your product forward.
Nice to know
A design system is more than a collection of visual building blocks and UI elements. It defines rules, structures, and shared principles for designing digital interfaces. This keeps your user interfaces consistent, usable, and scalable across products, services, and teams. Our UI experts recommend design systems because they address a common challenge in many digital products: maintaining consistency as complexity grows.
Types of user interfaces
Depending on the task and environment, different types of interfaces make sense. They shape how users interact with a system and which control concepts work best. Our UI designers take these differences into account from the start. They recommend and choose the right form of interaction based on real requirements like clarity and efficiency, not trends. This always happens in close collaboration with our user research teams.
For example, a touch interface works well in many cases, but in other situations, physical controls like knobs and buttons are the more robust and reliable choice. We help you find the right type of interface for your specific use case and tailor it to your users’ needs.
Graphical user interfaces are visual interfaces used in apps, web applications, machine panels, and embedded systems. In GUIs, we present content, functions, and states through layouts, typography, colors, and interactive elements. A clear visual hierarchy helps users quickly understand information and complete tasks reliably. GUI design is a core part of modern digital products.
Voice user interfaces enable interaction through speech. We use them where visual interfaces are limited or need to be complemented. Typical examples include assistant systems, smart home applications, industrial environments, and accessibility-focused use cases. Key factors for a good VUI are a clear dialogue structure, understandable feedback, and reduced interaction complexity.
Physical interfaces include haptic controls such as buttons, knobs, switches, and displays. We often recommend them in HMI environments like machines, systems, and devices. Through direct feedback like touch and resistance, they enable safe and precise operation, even in demanding conditions. The design, layout, and labeling of these elements have a strong impact on usability and trust.
Multimodal interfaces combine different types of interaction such as visual interfaces, voice, and physical controls. This approach is common in complex systems that need to support a wide range of usage scenarios. We bring together the strengths of each interface to create a seamless experience without overwhelming your users.
Intuitive interaction through a modern UI is a key focus for us. Your users should not struggle with technology, they should enjoy using your product and have a smooth experience with the application.
Oliver Kortekamp
Team Leader & PO at Oase
We consistently feel that slashwhy takes real ownership of the product. Everyone involved truly identifies with it, which sets them apart from other service providers.
Dr. Melanie Schuh
Product Management at W&H
With slashwhy, we have a partner who goes far beyond simply delivering code. They support the entire process from concept to implementation, truly identify with the product, and actively help improve it.
Friedrich Laube
Director Digital Products & Services Smart Home at Miele
The agile mindset of all slashwhy team members is impressive and genuinely contagious in the best possible way. We work together with slashwhy as equals in agile teams and reach our goals faster as a result.
Markus Rose
Director CHARX control Division Charging Infrastructure at Phoenix Contact
A key benefit of the solution developed with slashwhy is that we can continue evolving our series products while running new development projects in parallel.
Axel Schröder
Director Advanced Engineering at CLAAS E-Systems
We can save a completed commissioning process in the app and reuse it as a template, especially for large projects. This allows us to configure similar gates consistently and much more efficiently. It is a clear advantage and a strong benefit of the app.
Tobias Lange
Projektmanager at Hörmann
Global players and hidden champions
We recommend that any company working with software as a core part of its products, services, or processes invests in UI design, especially when people need to use it intuitively. Whether it is an app, a web application, or embedded software, as soon as users interact with it in their daily work, the user interface defines how quickly they find their way around, how efficiently they can work, and whether they actually enjoy using it.
UI design becomes even more critical when digital solutions are business critical or directly impact success. This is the case for customer apps, digital platforms, connected products, or complex control systems. It is not just about creating appealing interfaces, it is about building clear structures, intuitive interactions, and a consistent experience across all touchpoints.
User interface design is a core part of modern software development and has a strong impact on how clearly, intuitively, and efficiently digital products can be used. A clear visual design structures content, makes features easy to use, and helps users find their way even in complex applications.
As a development partner for custom software, slashwhy treats UI design as an integral part of the entire UX design process. Disciplines like user research, prototyping, UX testing, and user interface design work closely together to ensure that requirements are driven by real usage and translated into effective interfaces.
Depending on the application, different types of interfaces come into play, such as graphical user interfaces (GUI), voice user interfaces (VUI), or human machine interfaces (HMI). The right choice depends on the context of use and the needs of your users.
UI design becomes especially important when applications grow or start to reach their limits in everyday use. Common challenges include unclear structures, high error rates, or low acceptance. A well thought out interface helps reduce complexity, present information clearly, and improve the overall user experience.
Our UX teams work closely with development to bring design, technical implementation, and user needs together. This results in consistent, scalable interfaces that work reliably in real-world use.