We are looking for a Senior .NET 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.
- 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.
- Security mindset: practical experience remediating security findings (OWASP classes, secrets handling, crypto usage) in existing code; PCI / payments / fintech exposure is a strong plus.
- 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.
- English: fluent written and spoken English (B2+) for documentation, evidence packages and client calls.
We offer*:
- Flexible working format - remote, office-based or flexible
- A competitive salary and good compensation package
- Personalized career growth
- Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)
- Active tech communities with regular knowledge sharing
- Education reimbursement
- Memorable anniversary presents
- Corporate events and team buildings
- Other location-specific benefits
*not applicable for freelancers
Skills Required
- 6+ years of professional .NET development experience on large production systems
- Brownfield or legacy modernization experience
- Expert C# experience
- Expert ASP.NET experience, including MVC, Web API, and Razor Pages
- Hands-on experience with .NET Framework 4.5.x-era code and .NET 6+ migrations
- Experience with Entity Framework and EF Core
- Practical experience remediating security findings, including OWASP vulnerabilities, secrets handling, and cryptographic usage
- Fluent written and spoken English at B2+ level
- PCI, payments, or fintech experience
- Azure PaaS experience, including App Services, Functions, Service Bus, or Cosmos DB
- AWS experience, including Lambda, S3, SNS, or SQS
- Azure AD B2C experience
- Blazor experience
- SignalR experience
- Telerik or Kendo UI experience
What We Do
N-iX is a global software solutions and engineering services company that helps world’s leading organizations turn challenges into lasting business value, operational efficiency, and revenue growth using advanced technology. Whether you need to build a custom solution, modernize your digital product or acquire extra tech expertise - we have the experience and capabilities to ensure your success. With over 2,000 professionals in 25 countries across Europe and the Americas, N-iX offers expert solutions in cloud, data analytics, embedded software, IoT, AI, machine learning, and other tech domains. Being in business for over two decades, we have worked with dozens of industry-leading enterprises and Fortune 500 companies creating value across a wide variety of sectors, including finance, manufacturing, supply chain, retail, e-commerce, healthcare, and more. Our unique combination of business domain expertise and technical know-how enables us to effectively collaborate with ISVs, tech companies, and enterprises of all sizes. Thanks to the strong tech ecosystem and partnerships with AWS, GCP, Microsoft, SAP, OpenText, Snowflake, and others, we bring extra speed, scale and efficiency to more than 160 organizations across the globe. N-iX is recognized by numerous industry awards, such as CRN Solution Provider 500, Global Outsourcing 100 by IAOP, ISG Provider Lens™, Modern Application Development services providers by Forrester, etc
