Design and implement a payment-provider abstraction layer for a client-facing e-commerce application. Integrate card capture, payment, and refund flows with a new provider while minimizing PCI compliance exposure. Collaborate with delivery teams and client stakeholders amid incomplete ownership or documentation. The role requires modernizing large legacy .NET systems, remediating security issues, and supporting migrations from .NET Framework to .NET 6+.
Role Overview
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
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