Software engineering · Zagreb · Since 2009

We make software and hardware work together.

Design Zone 42 is a software engineering studio specialising in software–hardware integration and complex systems. We analyse, design, build and maintain systems in which hardware, software, infrastructure and data depend on one another.

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Founded in Zagreb, Croatia: 2009
Years of combined professional experience in software: 40+
Clients and distributed teams across Europe, North and Latin America, and Australia: Global
Personal contact with the people responsible for your project at every stage: Direct

Services

Engineered end to end, from the device to the dashboard.

01 Core focus

Software–hardware integration

We connect physical devices and equipment with the applications, data and infrastructure around them, whether we are designing a new system or modernising and extending an existing one.

Systems analysis and requirements
System and software architecture
Device communication and data exchange
Application software and backend services
Integration with third-party systems
Infrastructure, deployment and maintenance

Bespoke web applications

When off-the-shelf software falls short, we engineer what's missing.

Web applications and internal business systems built around how your organisation actually works. We analyse the underlying processes and business rules first, then design everything from the data model to the user interface.

Applied AI

AI integrated into your products and operations where it solves a concrete problem: language-model assistants, document processing, knowledge search and workflow automation.

Frontend & usability

Clear, efficient interfaces for detailed data and multi-step workflows, designed for the people who use them every day and built as maintainable frontend code.

Infrastructure & operations

Server administration, deployment and ongoing maintenance that keep your systems secure, up to date and available.

Systems analysis

From complexity to clarity.

Some of the most demanding software problems begin long before the first line of code is written.

Business rules are often scattered across spreadsheets, documents, existing applications and workflows that were never written down. We do not wait for a finished specification. We investigate these sources, reconstruct the logic and dependencies they contain and turn them into clear, implementable requirements, for new software as much as for the next stage of an existing system.

We understand the problem before we engineer the solution.

Analysis

We study processes, documents and existing systems to establish what the software must do.
Architecture

We structure data, components and interfaces around those findings, so the design follows real operational requirements.
Implementation

We build, test and deploy the software, and maintain it as your needs change.

Systems engineering

Complex systems. Thoughtful engineering.

Modern software rarely operates in isolation. It connects devices, applications, infrastructure and third-party technologies, often built by different vendors, to different standards and for different purposes.

Our expertise goes beyond connecting APIs or integrating existing products. We examine how a system behaves as a whole, identify its technical constraints and design solutions where standard approaches reach their limits.

We work across every layer involved, from device communication and custom components to applications and infrastructure, on new platforms and established ones alike.

We don't just connect technologies. We make them work as one.

About us

Deep technical expertise. Direct collaboration.

Founded in Zagreb in 2009, we are a small, independent studio that combines analytical thinking, software architecture and hands-on engineering with a practical understanding of how organisations work and how people use software.

You work directly with the people who analyse your requirements, design your systems and engineer your software. Decisions are discussed with those who make them, and the same people remain responsible for your system through maintenance and long-term support.

Four principles guide how we work:

TransparencyRealistic estimates and candid technical advice, including when a simpler solution would serve you better.
Clear communicationRegular progress updates and clear explanations of technical decisions, risks and trade-offs.
RespectYour budget, deadlines and data are treated with the same care as our own.
Long-term thinkingSystems designed to be maintained and extended for years, not rewritten.

Clients

From small businesses to international corporations.

We have developed business applications, specialist research software, institutional platforms, websites and systems that integrate multiple technologies for healthcare, research and academic institutions, non-profits and companies in technology, insurance and finance. Some have remained useful for many years, including applications later adapted to different operational purposes.

HuaweiTechnology
AllianzInsurance
Versance.aiAI · Capital markets
Croatian Academy of EngineeringAcademic
The Brave Phone, ZagrebNon-profit
Center for Brain ResearchResearch
Medical Faculty, University of ZagrebAcademic
Faculty of Food Technology and Biotechnology, University of ZagrebAcademic
Sisters of Charity Hospital, ZagrebHealthcare
Small and medium-sized businessesVarious industries

Team

The people you will work with.

Tomislav Vlahović

Managing Director & Lead Software Engineer

Software architecture · Systems engineering · Software–hardware integration

Tomislav is a software engineer and systems architect with more than 20 years of experience designing, developing and maintaining complex software systems. His expertise spans software architecture, backend development, software–hardware integration, infrastructure and third-party systems.

He specialises in understanding how different technologies interact, identifying architectural limitations and engineering custom solutions where existing products cannot meet technical requirements. His work combines system-level thinking with hands-on development, with a focus on reliability, maintainability and long-term operation. He also leads our work in applied AI.

tomislav.vlahovic@dizajnzona42.hr

Martina Hajsig Vlahović

Founder & Systems Analyst

Systems analysis · Requirements engineering · Business logic · User experience

Martina founded Design Zone 42 in 2009 and brings more than 20 years of experience in software development and digital solutions. With a background in science, she approaches complex problems through systematic analysis, pattern recognition and structured reasoning.

Her work sits at the intersection of business processes, technical requirements and user needs: uncovering the underlying business logic, identifying relationships and dependencies within fragmented and often undocumented information, and translating them into clear, actionable software requirements. Her experience in frontend development, usability and visual design informs how these systems are structured and used.

42@dizajnzona42.hr

Contact

Let's discuss your project.

Tell us about your system, goals and constraints, even if they are not yet fully defined. The initial consultation is free of charge, at our office in Zagreb or online.