Join to apply for the Senior Full Stack Engineer (.Net) role at Definely

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Join to apply for the Senior Full Stack Engineer (.Net) role at Definely

About The Role

We’re looking for exceptionally talented Senior Full Stack Engineers with deep expertise in .NET/C# and WPF to join our growing team.

About The Role

We’re looking for exceptionally talented Senior Full Stack Engineers with deep expertise in .NET/C# and WPF to join our growing team.

In this role, you will lead the full software development lifecycle: from design and implementation to testing, deployment, and ongoing support for our core LegalTech products. You’ll build and enhance rich WPF-based Windows desktop applications, scalable backend services, and cloud-integrated solutions. While the title includes “Full Stack,” this is not a traditional web development role; your focus will be on high-performance Windows applications and associated backend systems.

You’ll also play a key role in mentoring engineers, driving architectural improvements, and shaping engineering practices that ensure performance, maintainability, and innovation.



Key Responsibilities

Application Development

• Architect, design, and develop complex desktop applications using WPF and modern patterns like MVVM.
• Build and maintain robust .NET Framework and .NET Core backend services, APIs, and libraries.
• Implement modular application architectures to support scalability and maintainability.
• Integrate with cloud platforms (AWS, Azure) for distributed computing and storage.
  
  

• Lead design reviews, code reviews, and architectural discussions to ensure technical excellence.
• Collaborate with product managers, designers, and cross-functional engineers to deliver high-impact features.
  
  

• Champion best practices including SOLID, DRY, KISS, and test-driven development (TDD) to ensure code quality and building of new features.
• Leverage AI-assisted tools (e.g., GitHub Copilot, Claude Code) to streamline development and accelerate feature delivery.
• Perform code refactoring, increase test coverage, and improve legacy codebases.
• Apply performance and memory profiling techniques to ensure optimal runtime behaviour.
• Utilise dependency injection frameworks (e.g., Autofac) to write clean and decoupled code.
  
  

• Tackle complex technical challenges across frontend and backend systems.
• Design solutions with a strong emphasis on asynchronous programming, multithreading, and regular expression optimisation.
• Continuously improve system performance and developer experience through innovation and tooling.
  
  

• 5+ years of professional experience with .NET and C# across frontend and backend development.
• Deep expertise in WPF, including XAML, data binding, custom controls, UI animations, and MVVM.
• Strong experience building Windows desktop applications with attention to UI/UX design.
• Proficient in both .NET Framework and .NET Core.
• Familiar with dependency injection, modular architectures, and reusable components.
• Strong understanding of multithreading, async/await, and asynchronous design patterns.
• Experienced with regular expressions, especially in parsing or document-focused workflows.
• Proven use of performance and memory profilers to debug and optimise applications.
• Experience working with Visual Studio, JetBrains Rider, ReSharper, and modern DevOps pipelines.
• Experience with AI-assisted coding tools (e.g., GitHub Copilot, Claude Code) to accelerate development.
• Familiar with relational databases (e.g., PostgreSQL) and RESTful APIs.
• Strong grasp of Git and version control best practices.
• Strong communication, collaboration, and problem-solving skills.
• Comfortable in a fast-paced, agile environment.
  
  

• Prior experience in product-centric or startup environments.
• Experience with VSTO Word Add-Ins.
• Exposure to other AI-powered developer tools and workflows.
• Familiarity with modern cross-platform frameworks like .NET MAUI, Blazor, or Avalonia.
• Understanding of cloud-native design, distributed systems, and DevOps best practices.
  
  

• We offer a highly competitive salary that reflects your skills, experience, and contributions.
  
  

• Join a fast-growing startup where your ideas matter; experiment, innovate, and see your work come to life.
  
  

• Work in a truly meritocratic environment alongside ambitious, driven professionals who push each other to excel.
  
  

• Collaborate with some of the world’s top law firms, financial institutions, and multinational corporations.
  
  

• Enjoy a vibrant office in the heart of Aldgate with the option to work in a hybrid environment. We tend to come into the office 2-3 times a week, although you can come in more!
  
  

• Access top-tier training, mentorship, and continuous support to advance your career.
  
  

• Enjoy 25 days of holiday per year, plus UK bank holidays, to recharge and unwind.
  
  

• Secure your future with our competitive pension scheme.
  
  

• Access to Vitality healthcare, including dental and optical.
  
  

• Work in a way that suits your lifestyle, with the freedom to balance professional and personal priorities.
  
  

• We support working parents with generous parental leave policies that go far beyond statutory requirements.
  
  

• Save on a new bike and accessories while promoting a healthier, more sustainable commute.
  
  

• Saving working parents lots of money through our salary sacrifice scheme!
  
  

• Get the tools you need to perform at your best, from cutting-edge tech to ergonomic office setups.
  
  

Seniority level

• Seniority level

  Mid-Senior level

Employment type

• Employment type

  Full-time

Job function

• Job function

  Engineering and Information Technology

• Industries

  Software Development

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