Lead .NET Developer (Full-Stack)

We are looking for an experienced Lead .NET Engineer to join an international project focused on developing and modernising an established lending platform used by financial institutions across the UK and Europe.

Initially, you will focus on hands-on full-stack development, delivering changes across a complex system built primarily on C#, .NET Framework 4.x, ASP.NET and SQL Server, with some legacy components using Delphi 7 and COM/COM+.

Over time, your role will evolve towards technical leadership, architectural improvements and AI adoption. You will help shape the platform's technical direction, support the existing development team and contribute to its future growth.

We are looking for someone who combines strong engineering expertise with technical leadership experience, understands complex legacy systems and knows how to modernise them without disrupting existing business operations.

IN SHORT:

🌎 Remote work or from one of our offices
💰 160 - 190 PLN/h + VAT
☑️ B2B contract

Your Daily Missions

• Developing and maintaining a complex lending platform using C#, .NET Framework 4.x, ASP.NET and SQL Server.

• Delivering full-stack changes end to end, from requirements analysis through implementation, testing and code review.

• Developing and optimising T-SQL stored procedures, SQL Server Agent jobs and database queries.

• Working with ASP.NET MVC/WebForms, JavaScript, jQuery, AJAX and Bootstrap.

• Maintaining APIs, integrations and background-processing services.

• Working with legacy components, including Delphi 7, COM/COM+ and VB.NET, where required.

• Improving code quality, system architecture and maintainability through incremental modernisation.

• Using AI coding assistants for development, code analysis, troubleshooting and technical documentation.

• Collaborating with developers, business analysts and stakeholders to deliver reliable solutions.

• Gradually taking ownership of technical architecture, engineering standards and the product's technical direction.

• Mentoring engineers, sharing knowledge and supporting the adoption of AI-assisted development practices.

The Essentials We’re Seeking

• Strong commercial experience with C# and .NET Framework 4.x, including production application development and maintenance.

• Advanced knowledge of SQL Server and T-SQL, including stored procedures, query optimisation and SQL Server Agent jobs.

• Hands-on experience with ASP.NET MVC or WebForms and frontend technologies such as JavaScript, jQuery, AJAX and Bootstrap.

• Experience developing and maintaining REST APIs, system integrations and background-processing services.

• Experience working with complex legacy systems and modernising existing applications incrementally.

• Previous experience as a Tech Lead or Software Architect, including architectural decisions, engineering standards and mentoring developers.

• Ability to take technical ownership, influence decisions and introduce improvements within experienced development teams.

• Practical experience using AI coding assistants (GitHub Copilot, Claude Code, Cursor, OpenAI Codex or similar) in daily development, including critical validation of generated code.

• Commercial experience in a regulated or financial domain, such as lending, banking, payments, insurance, consumer credit, collections or KYC/AML.

• Understanding of auditability, change control, data integrity and compliance requirements in regulated environments.

• Strong analytical and problem-solving skills, a proactive mindset and the ability to work independently.

• Strong written and spoken English (B2+ minimum, C1 preferred).

Nice-to-haves

• Experience with Delphi 7, COM/COM+, VB, VB.NET, classic ASP or XSLT.

• Knowledge of older Angular applications or SignalR.

• Experience with SOAP/ASMX, Windows Services, RabbitMQ, MSMQ, IBM MQ, XML or EDI.

• Experience migrating applications from .NET Framework to modern .NET.

• Experience in lending, asset finance, consumer credit or debt collection.

• Knowledge of SEPA, UK Direct Debit, card payments or financial system integrations.

• Familiarity with IdentityServer, ASP.NET Identity, Redis, Adobe Sign or DocuSign.

• Experience with Azure DevOps, TeamCity or Octopus Deploy.

• Previous experience working in a software product company or software vendor environment.