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A WinJS expert is a developer who specializes in the Windows Library for JavaScript, building HTML5, CSS3, and JavaScript applications for Windows 8, Windows 10, and Universal Windows Platform environments. WinJS provides controls, animations, data binding, and navigation patterns that make web technologies behave like native Windows apps. Hiring a WinJS specialist gives you targeted expertise for legacy Windows Store apps, in-house enterprise tools, and modernization projects that rely on the WinJS framework.

What a WinJS expert delivers

WinJS developers build, maintain, and migrate JavaScript-based applications that run inside the Windows runtime. The framework was originally released by Microsoft to let web developers ship Windows Store apps using familiar tooling, and it remains in active use across enterprise environments, kiosk software, and line-of-business applications. A skilled WinJS consultant translates business requirements into responsive, touch-friendly interfaces that integrate cleanly with Windows APIs.

Commercially, this skill matters when your organization holds existing WinJS code that needs continued support, bug fixing, feature extension, or controlled migration to newer stacks like UWP with TypeScript, React Native for Windows, or WinUI. A specialist protects your investment, reduces technical debt, and keeps mission-critical apps running on supported Windows versions.

Core services and deliverables

Tools and technologies WinJS specialists use

A competent WinJS developer works fluently across the Microsoft ecosystem and the wider JavaScript toolchain. Expect proficiency with Visual Studio, Blend for Visual Studio, the Windows SDK, and the Windows App Certification Kit. They should also be comfortable with HTML5, CSS3, JavaScript ES6, TypeScript, jQuery, and Knockout.js where projects mix paradigms.

Adjacent skills that strengthen a WinJS engagement include Universal Windows Platform development, C# and XAML, WinRT components, Cordova for cross-platform packaging, Git version control, and Azure services for backend integration. Many WinJS contractors also bring experience with Node.js tooling, Webpack, and Jasmine or Mocha for unit testing.

Industries and use cases

WinJS expertise is most often needed in industries that deployed Windows 8 or Windows 10 line-of-business apps and continue to depend on them. Common scenarios include retail point-of-sale systems, healthcare clinical workstations, manufacturing floor dashboards, education and e-learning kiosks, logistics handheld applications running on Windows tablets, and government or defense apps with long support cycles. Media and entertainment companies also use WinJS for catalog browsing apps and second-screen experiences.

How to evaluate WinJS candidates

Look for developers with shipped Windows Store apps, public GitHub repositories containing WinJS code, and clear experience with the Windows Runtime. Strong candidates can describe the WinJS lifecycle, navigation model, and the differences between WinJS 1.0, 2.0, and 4.x. Portfolio markers worth verifying include published Microsoft Store listings, enterprise app screenshots, and contributions to the open-source WinJS project on GitHub.

Useful interview questions to ask:

Why hire WinJS experts on Freelancer.com

WinJS is a niche skill, which makes finding qualified developers locally difficult. Freelancer.com gives you access to a global pool of vetted JavaScript and Windows platform specialists, including developers who shipped commercial WinJS apps during the framework's peak and have continued to maintain them. You can compare portfolios, ratings, completion rates, and verified reviews before you commit. Whether you need a short bug fix, a long-term maintenance contractor, or a migration architect, you can post a project on Freelancer.com and receive competitive bids from freelancers who match your stack and budget.

Ready to extend, maintain, or migrate your Windows JavaScript application? Post a project on Freelancer.com today and connect with skilled WinJS experts ready to deliver.

What are the steps to hiring a freelance WinJS expert?

Hiring a WinJS developer works best when your brief reflects the technical realities of the codebase. Because the framework is specialized, a precise project description filters out generalists and attracts JavaScript developers with genuine Windows platform experience. The three steps below walk you through posting, reviewing, and awarding the work.

Step 1: Post your project on Freelancer.com

The brief is the single biggest factor in bid quality. A vague post attracts vague proposals, while a specific brief brings developers who can speak to your exact WinJS version, integration points, and target Windows builds. Head to the post project page , fill in the scope, timeline, and budget, and publish the project for freelancers to bid on.

Step 2: Review bids from freelancers

Bids are short proposals, not just price quotes. A strong WinJS bid shows the freelancer has read your brief, understands the framework's quirks, and has a realistic plan. Use the proposals to shortlist developers whose technical reasoning matches the work, and use Freelancer.com chat to ask follow-up questions before deciding.

Step 3: Evaluate freelancers and award the project

The final decision should combine proposal quality with profile evidence. Review portfolio depth across multiple Windows or JavaScript projects rather than a single highlight, and pay attention to written client reviews that mention reliability, communication, and technical accuracy. Consistency across many projects matters more than one impressive screenshot.