Production-ready fintech platform for a payments startup

When Aircash set out to launch Croatia’s first regulated electronic money platform, the goal wasn’t just to build another app, it was to create a reliable financial infrastructure that could handle real transactions from day one. That meant speed mattered, but stability and scalability mattered even more.

We joined early, when the product still needed validation. The focus was clear: turn an ambitious idea into a working proof of concept, fast enough to test the market, but solid enough to grow into a production system.

At this stage, many fintech products fail by moving quickly and accumulating technical debt. We took a different approach. We focused on delivering a lean, functional system while ensuring that every architectural decision supported long-term growth.

Instead of building shortcuts, we designed a backend that could scale, integrate, and evolve as the product matured. This gave the Aircash team confidence to move forward without worrying about rebuilding core systems later.

A key part of the platform’s value came from its ability to connect with external systems. This included integrations with major Croatian service providers and enabling money transfers through a nationwide retail network.

These weren’t simple plug-ins. Each integration required careful handling of transactions, reliability, and data consistency which are, as we all know, areas where small mistakes can quickly become expensive.

We built these integrations with a focus on robustness and flexibility, ensuring that new partners could be added without reworking the entire system.

To support both mobile and partner ecosystems, we implemented a REST API-driven architecture using .NET and MS SQL Server.

This approach allowed:

• The mobile application to communicate seamlessly with the backend
• Third-party services to integrate without friction
• The platform to expand without major architectural changes

For the Aircash team, this meant one thing: faster growth with fewer technical constraints.

Beyond the core platform, we developed an Angular-based admin interface that allowed the team to manage integrations and system configurations without relying on developers.

This reduced operational bottlenecks and gave stakeholders direct control over key business processes, which is critical in fast-moving fintech environments.

Fintech platforms don’t get second chances when it comes to reliability. From the beginning, we focused on clear system boundaries, predictable behavior, and maintainable code.

This helped:

• Avoid hidden complexity early on
• Reduce the risk of failures as usage increased
• Make future development faster and safer

For a growing platform, that translates directly into lower long-term cost and higher investor confidence.

By the end of the engagement, Aircash had more than just a prototype. They had a working, extensible backend platform that supported real integrations, real transactions, and real growth.

Most importantly, they avoided the common trap of early-stage products: building something that works today but breaks tomorrow.

Instead, they moved forward with a system designed to scale both technically and commercially giving them a strong foundation for everything that followed.