OpenSilver

OpenSilver is a powerful, open-source reimplementation of Microsoft Silverlight, designed to bring legacy .NET applications into the modern web era. It empowers developers to migrate existing Silverlight and Windows Presentation Foundation (WPF) applications to run on any modern browser and operating system, including Windows, macOS, Android, iOS, and Linux. By leveraging WebAssembly, OpenSilver compiles C#, F#, VB.NET, and XAML code into high-performance, client-side web applications, eliminating the need for browser plugins and breaking free from the limitations of Internet Explorer.

The core mission of OpenSilver is to provide a seamless and cost-effective migration path, saving companies from expensive and time-consuming rewrites. It boasts near-perfect compatibility with Silverlight and extensive support for WPF, allowing for up to 100% code reuse. This ensures that the migrated application maintains its original look, feel, and functionality, which minimizes the need for user retraining and updating documentation. The platform also introduces modern features, including an AI-enhanced drag-and-drop UI designer and compatibility with contemporary tech stacks like Blazor, React, and Angular.

How to use OpenSilver

Getting started with OpenSilver can be approached in several ways depending on your project needs:

1. Do-It-Yourself (DIY) Migration: Developers can download the free, open-source OpenSilver SDK to begin migrating their Silverlight or WPF applications on their own. The process involves opening the existing project in Visual Studio, adding the OpenSilver NuGet package, and compiling. For assistance, OpenSilver offers professional support plans and a Performance Optimization Pack to help identify bottlenecks and implement best practices.
2. End-to-End Migration Service: For organizations seeking a turnkey solution, the Userware team (the creators of OpenSilver) offers an all-inclusive migration service. Their experienced team handles the entire process, from code analysis to final deployment, guaranteeing a result that is identical to the original application at a fraction of the cost of a rewrite. You can get a quick quote by uploading your application's XAP file.
3. New Application Development: OpenSilver is not just for migration. It is also a robust framework for building new, rich, cross-platform web applications from scratch using .NET and XAML. With its MAUI Hybrid integration, developers can even target iOS and Android, creating a single codebase that runs everywhere.

Core Features of OpenSilver

• High Compatibility: Extensive support for Microsoft Silverlight APIs and a growing list of WPF features, ensuring maximum code reuse.
• Cross-Platform & Cross-Browser: Applications run natively in all modern browsers (Chrome, Firefox, Safari, Edge) on any desktop or mobile OS via WebAssembly.
• Multi-Language Support: Develop using your preferred .NET language: C#, VB.NET, or F#.
• AI-Powered UI Designer: Features a drag-and-drop XAML designer for Visual Studio Code (and online at XAML.io) with AI-enhanced capabilities like smart anchoring and alignment to accelerate UI development.
• MAUI Hybrid Integration: Extend WPF applications to run as native apps on iOS and Android, in addition to the web, sharing the same UI and business logic.
• Modern Tech Stack Integration: OpenSilver components can be embedded within Blazor, React, or Angular applications, allowing for gradual modernization or mixed-technology solutions.
• Legacy Tech Support: Includes compatibility packs for technologies like RIA Services and LightSwitch, preserving critical backend integrations.
• Open Source: The core SDK is open-source, fostering community collaboration and transparency.

Use Cases for OpenSilver

OpenSilver is ideal for enterprises and developers facing the challenge of outdated technology. A prime example is the migration of a large-scale project management system for Repton Projects. Their legacy Silverlight application, which used Telerik controls and RIA Services, was successfully migrated to OpenSilver. The new version retained its familiar interface, performed faster, and preserved over 99% of the original C# and XAML code. This resulted in a cost and time saving of at least 3x compared to a complete rewrite, allowing them to continue serving their customers on a future-proof platform.

Other key use cases include:

• Modernizing internal Line-of-Business (LOB) applications stuck on Internet Explorer.
• Extending complex WPF desktop applications to the web and mobile devices to reach a wider audience.
• Developing new, feature-rich data visualization dashboards and enterprise resource planning (ERP) systems that require a robust, client-side UI.

Advantages of OpenSilver

The primary advantage of OpenSilver is its ability to dramatically reduce the cost, time, and risk associated with application modernization. Key benefits include:

• Massive Cost & Time Savings: Avoids the 3-6x higher cost and longer timeline of a full rewrite from scratch.
• 100% UI and UX Parity: The migrated application looks and functions identically to the original, eliminating user retraining costs.
• Risk Mitigation: Preserves years of investment in a stable, proven codebase instead of introducing the risks of a new system.
• Future-Proof Technology: Moves applications to a modern, standard-based stack (WebAssembly) that is actively developed and supported on all platforms.
• Expert Support: Direct access to the core engineering team for dedicated migration and development support.

Pricing and Plans

While the OpenSilver SDK is open-source and free to use, the company offers a range of paid professional services and support subscriptions to ensure project success. These plans are designed for businesses that require expert guidance, dedicated development resources, or performance optimization.

• OpenSilver Specialist Consultant: Starts at $2,733/month for up to 10 hours of expert consultation, bug-fixing, and guidance.
• OpenSilver Dedicated Developer: Starts at $5,177/month for 40 hours of a dedicated developer from the core team.
• OpenSilver Dedicated Developer Plus: Starts at $8,179/month for up to 70 hours of dedicated monthly support.
• Performance Engineering Pack: A one-time package for $15,000 that includes 100 hours with a senior architect to identify and resolve performance bottlenecks.
• End-to-End Migration: Custom pricing is available based on project scope. A quick quote can be requested via their website.