Senior .Net Full-Stack Engineer

Location: European Union

Department: Finalsite Team

N-iX is a global software development service company that helps businesses across the globe create next-generation software products. Founded in 2002, we unite 2,400+ tech-savvy professionals across 40+ countries, working on impactful projects for industry leaders and Fortune 500 companies. Our expertise spans cloud, data, AI/ML, embedded software, IoT, and more, driving digital transformation across finance, manufacturing, telecom, healthcare, and other industries. Join N-iX and become part of a team where your ideas make a real impact.

We are looking for a Senior .NET Fullstack Engineer to work on migrating a client-facing e-commerce/store application's payment processing from its current gateway to a new payment provider.

Key Responsibilities

• Design and implement an abstraction layer that decouples the application from a single payment provider, enabling multiple providers to operate in parallel.
• Implement the integration with the new payment provider, including the card-capture and payment/refund flows, in a way that minimizes the application's compliance exposure.
• Collaborate closely with a small delivery team and client-side stakeholders where ownership or documentation is incomplete.

Requirements & Qualifications

• Experience: 6+ years of professional .NET development on large production systems; brownfield / legacy modernization experience is mandatory — this is not a greenfield role.
• Core stack (Must-Have): expert C# and ASP.NET (MVC, Web API, Razor Pages); hands-on with both .NET Framework 4.5.x-era code and .NET 6+ migrations; EF / EF Core.
• Frontend (Must-Have): solid Angular, React and TypeScript for upgrading and stabilizing existing UIs.
• Security mindset: practical experience remediating security findings (OWASP classes, secrets handling, crypto usage) in existing code; PCI / payments / fintech exposure is a strong plus.
• English: fluent written and spoken English (B2+) for documentation, evidence packages and client calls.
• Nice-to-Haves: Azure PaaS (App Services, Functions, Service Bus, Cosmos DB); AWS (Lambda, S3, SNS/SQS); Azure AD B2C; Blazor; SignalR; Telerik / Kendo UI.