Actify – Supporting healthier lives through habit building

Actify is an initiative by Zilveren Kruis, one of the largest health insurance providers in the Netherlands and part of the Achmea Group. Achmea is the biggest insurer in the Netherlands and among the largest in Europe, with other well-known brands such as Centraal Beheer and Interpolis.

The app is offered as a complementary digital service. Its main focus is helping people build healthy habits step by step through practical content and small actions. These habits are supported by recipes, meditations, workouts, personal goal selection, integrations with step counters and health apps, and a wide catalogue of short challenges.

The app is free for anyone to use, but it is particularly aimed at Zilveren Kruis clients. Its core idea is that small changes, repeated over time, lead to long-term improvements in wellbeing. The project reflects a growing shift in the healthcare sector towards preventive solutions that go beyond traditional treatment.

To learn more about the Actify app, click here.

The development of Actify required a broad and multi-layered approach, spanning mobile applications, backend systems, integrations, content management and continuous delivery. It was not a one-time build but an evolving process that demanded both technical expertise and a flexible way of working.

At the outset our role was to translate Actify’s initial concept into a concrete roadmap. Together with the client’s team we defined user stories, prioritised a backlog and estimated delivery timelines. Early mockups provided the first direction, but many details were shaped collaboratively during workshops with the Product Owner and health professionals. This close cooperation allowed us to refine ideas quickly, validate them with users and focus on delivering value from the very first iterations. Working in Scrum gave us the structure to release incrementally, gather feedback and continuously adapt the product based on real-world insights.

For the mobile experience we built applications for both iOS and Android using React Native. This ensured a shared codebase that saved development time while still allowing a smooth, native-like user experience. Over the years we introduced guided challenges, healthy recipes, meditations and short workouts, supported by integrations with step counters and health apps. A strong emphasis on user experience shaped every release: wireframes and prototypes were tested with real users to ensure accessibility, clarity and simplicity.

Behind the scenes, we designed and maintained a robust backend that evolved together with the product. What started as a virtual machine-based setup grew into a modern cloud environment capable of scaling efficiently and reliably. The backend communicates with the mobile apps via secure APIs and connects to a wide range of external services, from wearable data providers and behaviour change programmes to notification platforms and analytics tools.

An important part of the system is Actify’s machine learning engine for personalised content recommendations (BML). Originally developed by the Dutch team, responsibility for its further development and maintenance is now shared with DO OK. To support this, our dedicated data engineer joined the project team, focusing on enhancing the algorithm and ensuring it remains a reliable foundation for delivering tailored user experiences.

To keep the content fresh, we developed a custom content management system that allowed non-technical editors to publish new recipes, challenges and programmes without relying on developers. This capability proved essential for running seasonal campaigns and supporting group challenges.

All of these efforts were part of an ongoing, collaborative process. Over several years of uninterrupted work with Actify we have delivered new features, expanded integrations and supported multiple redesigns. The result is a product that has been able to evolve continuously, maintaining its relevance and impact while reaching an ever-growing audience.

A project of this scale required solving multiple technical and product challenges.

One of the most demanding areas was data integration. The app needed to process information coming from different wearables and health services, each with its own formats and standards. In the early stages we experimented with direct connections, but as the product matured we shifted to integrating through external providers that aggregate wearable data via SDKs. Our role was to implement and maintain these integrations within Actify’s backend, ensuring that the data was processed consistently and securely. All sensitive information was encrypted both in transit and at rest, and anonymisation techniques were applied to support reporting without exposing personal details.

Scalability was another key challenge. As the user base grew from a few thousand to tens of thousands, the system had to handle spikes in traffic, especially during national campaigns launched by Zilveren Kruis. We addressed this by introducing asynchronous processing, database partitioning and replication, and migrating the backend to Kubernetesfor more efficient scaling.

Keeping users engaged over time was equally critical. Together with Actify we introduced features such as themed mini-programmes, team challenges and a variety of habit categories, making the experience more interactive and adaptable to user preferences. Performance optimisation and monitoring ensured that the app remained stable and responsive, which was essential for user retention.

Finally, regulatory requirements shaped many of our decisions. By following healthcare standards and applying strict security measures, we ensured that the app could operate confidently within the highly regulated health sector.

Through these combined efforts the app was able to stay reliable, engaging and scalable while supporting a growing community of users.