Lead .Net Full-Stack Engineer (with Angular or React)

We are looking for a Lead .Net Full-Stack Engineer (with Angular or React) to join a dedicated delivery team working on a high-visibility engagement with a US-based payments technology company undergoing a strategic carve-out into a standalone business entity.
The platform processes card payments end-to-end for thousands of institutional customers and includes multiple production-grade .NET applications, such as a central payment gateway, a registration platform with an encrypted card vault, an AWS-native ticketing and point-of-sale solution, and a large commerce application with a single-tenant database model.

This is a fast-paced, security-focused modernization initiative with a hard 3-month delivery window. The team is responsible for performing security remediation, upgrading legacy frameworks and dependencies, and supporting the separation of Azure and AWS environments into an independent infrastructure landscape. The role offers direct exposure to CTO-level stakeholders and the possibility of continuing into a longer-term platform re-architecture phase.

Responsibilities:

• Remediate security findings across ASP.NET applications (MVC, Web API, Razor Pages), including issues related to secrets management, cryptography, token handling, injection vulnerabilities, and sensitive-data logging.
• Upgrade legacy .NET Framework applications to supported versions and migrate components to .NET 6+/8 where feasible.
• Modernize and stabilize frontend dependencies across Angular, React, TypeScript, and Telerik/Kendo UI codebases.
• Investigate and reverse-engineer brownfield systems, including legacy components, to understand data flows and payment-processing logic.
• Collaborate closely with the client’s retained engineering team, working effectively even in areas with limited documentation or SME coverage.
• Contribute to validation and retest activities by preparing evidence packages, deployment logs, and before/after remediation artifacts.
• Support CI/CD-driven delivery and ensure changes are shipped with appropriate testing, QA validation, and rollback procedures.
• Participate in technical discussions around future platform modernization and integration initiatives.

Requirements:

• 6+ years of professional experience in .NET development on large-scale production systems.
• Strong expertise in C# and ASP.NET (MVC, Web API, Razor Pages).
• Hands-on experience working with both .NET Framework 4.5.x-era applications and .NET 6+/8 modernization or migration efforts.
• Solid experience with Entity Framework / EF Core.
• Strong frontend skills with Angular, React, and TypeScript.
• Proven experience working on brownfield or legacy modernization projects.
• Practical experience remediating security vulnerabilities and applying secure coding practices (OWASP-related issues, secrets handling, cryptography, authentication/session management).
• Ability to work independently in complex, partially documented environments.
• Upper-Intermediate English (B2+) or higher.

Nice to have:

• Experience in payments, fintech, PCI DSS, or other security-sensitive domains.
• Experience with Azure PaaS services (App Services, Functions, Service Bus, Cosmos DB).
• Experience with AWS services (Lambda, S3, SNS/SQS).
• Familiarity with Azure AD B2C.
• Experience with Blazor or SignalR.
• Experience with Telerik / Kendo UI components.

• Experience working in M&A, carve-out, or large-scale platform separation programs.

   

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