We are seeking an experienced Lead Full Stack Engineer to join a high\-impact, strategic technology initiative. Our mission is to evolve a core business application for a market\-leading enterprise, proactively transforming the platform into a secure, maintainable, and high\-performance architecture. As the team's technical pillar, you will be responsible for guiding the hands\-on transformation of a legacy stack (.NET Framework 4\.5\.2, Angular 6\) into a modern, decoupled, API\-driven architecture, building the foundation for future innovation and scale. **What You'll Do:** ------------------- * **Lead the hands\-on architecture and development** for the complete modernization of a flagship business application. * **Guide the backend migration** from the legacy .NET Framework 4\.5\.2 to .NET 10\. This includes replacing the OWIN\-based hosting infrastructure with native ASP.NET Core middleware and refactoring code to remove System.Web dependencies (e.g., HttpContext, Session). * **Spearhead the complex frontend migration** from Angular 6 to Angular 20\. You will manage an incremental, version\-by\-version approach to mitigate risk, addressing numerous breaking changes and updating third\-party libraries. * **Collaborate with the Solution Architect** to implement and enforce a strict "API\-first" decoupled architecture, ensuring a clean separation between the new SPA frontend and the .NET 10 backend. * **Address and resolve critical dependency challenges**, replacing dozens of incompatible NuGet packages (e.g., Microsoft.Owin, Swashbuckle.Core, MySql.Data.Entity) and outdated JavaScript libraries. * **Work closely with the DevOps Engineer** to build and optimize multi\-stage CI/CD pipelines in Azure DevOps using YAML. * **Mentor and guide the team's Senior and Middle engineers**, establishing best practices and ensuring code quality within the new architecture. * **Partner with the QA team** to support the creation of the manual regression test suite and validate functionality during continuous in\-sprint testing phases. **What We're Looking For:** --------------------------- * Extensive senior\-level software engineering experience with a proven track record of leading complex technical modernization projects. * **Deep mastery of the .NET ecosystem**, including experience with both legacy .NET Framework 4\.x (particularly ASP.NET) and modern .NET Core / .NET 10\. * **Expert\-level Angular skills**, specifically with demonstrable experience in complex migrations across multiple major versions (e.g., migrating from Angular 6 or similar). * Experience architecting and migrating monolithic (tightly\-coupled) applications to decoupled, API\-driven Single Page Application (SPA) architectures. * Solid hands\-on experience with **Azure DevOps**, particularly building and managing YAML\-based CI/CD pipelines. * Proven experience with **MySQL**, including upgrading data access drivers (e.g., from MySql.Data to MySql.EntityFrameworkCore) and refactoring data access logic. * Familiarity with the challenges of replacing legacy .NET components like System.Web, OWIN, and Microsoft.AspNet.WebApi.Core. * Strong communication and collaboration skills to work effectively with multidisciplinary technical teams (DevOps, QA, DBAs) and manage project dependencies. * Exceptional command of written and spoken English. **Why Join Us?** ---------------- * Take the primary technical leadership role in a critical, high\-impact modernization project. * Solve complex technical challenges spanning deep framework migrations and a complete architectural transformation. * Work with a dedicated, multidisciplinary team of architects, engineers, and QA specialists focused on a clear objective. * See the direct results of your work as you transform a core application into a modern, secure, and high\-performance platform. * Be part of a quality first company, multiple options for getting new education and certifications. **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