sofString

Who Are We?

sofString is a bold and aspiring company with the sole purpose of delivering high-quality software solutions for businesses of all industry.

Our team consists of highly skilled experts specialized in various fields of software development. We use modern IT Project Management tools and provide top-notch professionals to develop software products according to customer’s requirements. From an application for an online shop, through a time management system all the way to customized software - whatever the business wants, we can do it!

 

 

About the job Ref220725156CCCB Senior Frontend Software Engineer WinUI 3/Desktop

We are seeking an expert Frontend Software Engineer to architect and lead the development of a groundbreaking, high-performance Windows desktop application. As a foundational member of the team, you will have complete ownership over building a sophisticated user experience from scratch using WinUI 3. This role demands a master of the modern Windows development stack who can transform complex requirements into a fluid and visually stunning interface, complete with interactive data visualizations, high-throughput grids, and integrated video streaming.

If you are a seasoned engineer with proven WinUI 3 experience and a passion for crafting world-class desktop applications, this is a career-defining opportunity to set the technical vision for a flagship product.

The core purpose of this role is to serve as the technical authority and principal developer for our application’s user interface. You will drive all major architectural decisions for the frontend, establish best practices, and implement the most critical and complex UI features. Your mission is to build a scalable, performant, and maintainable UI architecture that not only meets today‘s needs but is also robust enough to support future innovation.

 

Start: ASAP

Duration: 6 months (with an extension option)

 

 

Responsibilities:

* Architect and lead the end-to-end development of the application's frontend using WinUI 3, XAML, and C#.
* Own the technical strategy for the UI layer, making critical decisions on component libraries, state management, and architectural patterns.
* Design and implement highly complex, interactive UI components, including custom-built data visualizations, high-performance virtualized data grids, and sophisticated custom controls.
* Engineer a robust and intuitive multi-window and multi-monitor experience.
* Implement robust client-side logic to communicate with backend services,
* consuming both high-performance gRPC streams and standard RESTful APIs.
* Integrate and optimize real-time video streaming components within the WinUI 3 framework.
* Champion and enforce the MVVM (Model-View-ViewModel) design pattern, dependency injection, and other best practices to ensure a decoupled and scalable codebase.
* Rigorously profile, diagnose, and resolve performance bottlenecks related to UI rendering, data binding, and memory consumption.
* Collaborate with product and backend teams to define and refine technical requirements, ensuring frontend capabilities align perfectly with backend services.
* Partner with QA and DevOps to define and implement a comprehensive UI test automation strategy, ensuring the application is architected for testability.
* Mentor other engineers (as the team grows) and establish the gold standard for code quality, testing, and development processes for the frontend.

 

 

Requirements:

* 7+ years of professional software engineering experience, with a recent focus on frontend/UI development.
* Proven, hands-on professional experience building and shipping applications with WinUI 3 and the Windows App SDK.
* Expert-level proficiency in C# and an in-depth understanding of the .NET ecosystem (.NET 6/7/8).
* Experience building clients that consume backend services using both REST APIs and gRPC.
* Mastery of a XAML-based technology (WPF, UWP), with a recent and primary focus on WinUI 3.
* Expert-level knowledge and practical application of software architecture and design patterns, especially MVVM, Dependency Injection (DI), and Repository patterns.
* Demonstrable experience architecting solutions for complex UI challenges, such as handling large datasets, virtualization, and multi-threading in the UI.
* Deep experience with asynchronous programming (async/await) and its practical application in creating responsive user interfaces.
* A bachelor’s degree in Computer Science, Engineering, or a related field, or equivalent professional experience.

 

Preferred Skills:

* Experience developing custom controls from the ground up in WinUI/XAML.
* Familiarity with advanced performance and memory profiling tools for .NET (e.g., PerfView, dotTrace, dotMemory).
* Experience with UI automation frameworks for Windows applications (e.g., WinAppDriver, Appium, Playwright).
* Knowledge of video streaming protocols (e.g., RTSP, WebRTC) and their integration challenges within a native desktop client.
* Experience setting up and maintaining CI/CD pipelines for Windows applications using MSIX packaging (e.g., Azure DevOps, GitHub Actions).
* A strong portfolio or GitHub profile showcasing advanced desktop application development projects.

 

What we offer:

* Remote opportunities for IT-professionals located in Bulgaria
* Temporary contract opportunities
* Flexible work hours
* Friendly atmosphere and collaborative team
* Interesting projects with diverse clients and many exciting challenges
* Opportunities for long-term professional development in a quickly growing company

 

If this role would fit your personal interests and plans for professional development please send us your CV.

Only short-listed candidates will be contacted.

Software Development

Project management

Windows Application

Data

Automation

DevOps

Testing

Design Pattern

Desktop Applications

Ux writing

Time management

Web Development

MvvmCross

Support

Innovation

Continuous Integration

Azure

Test Automation

Responsive Design

Mobile App Development

XAML

ASP.NET

RESTful API

gRPC

MVVM

Dependency Manager

Asynchronous Programming

CI/CD

GitHub Actions

Video streaming

DTrace

Ui test automation

Senior Frontend Software Engineer WinUI 3/Desktop