Microsoft open sourcing more developer tech: .NET Compiler Platform, C#, Visual Basic, more
Microsoft open sources more of its .Net technologies — Summary: From the truth-is- stranger-than-fiction files, Microsoft — along with its mobile-dev tool partner Xamarin …
Context & Ripple Effects
The announcement lands mid-Build 2014, a day after Microsoft unveiled Windows Phone 8.1 at the same conference, and it arrives bundled with a broad Azure push — new load management for sites, a raised 99.95% database uptime commitment — that frames the open-sourcing move inside a wider courtship of developers.
The scope is what makes it travel: confirmed details cover not just the .NET Compiler Platform, C# and Visual Basic, but also the WinJS JavaScript library for Windows-styled controls, opened up explicitly because it can help developers build cross-platform applications faster, with mobile-tools partner Xamarin working alongside Microsoft. Pickup across TechCrunch, The Next Web, ReadWrite, GeekWire, eWeek and Microsoft's own blog on the same day shows an unusually wide audience for what is, mechanically, a licensing change.
First-order effects
- Developers gain direct access to the C# and Visual Basic compiler sources and the .NET Compiler Platform, letting third parties extend, fork or embed Microsoft's language tooling rather than waiting on Redmond's release cadence.
- Xamarin's role as the sanctioned route for .NET-based mobile development hardens overnight, since the company now co-stewards technologies Microsoft itself is opening rather than merely interop-ing with a closed stack.
Second-order effects
- Opening C#, VB and WinJS weakens the argument that targeting Microsoft platforms means accepting Windows-only lock-in, pressuring Microsoft's own platform teams to compete on tooling quality instead of ecosystem captivity.
- Tooling vendors and IDE makers building on the .NET Compiler Platform get a supported extension surface, shifting competitive energy in the dev-tools market toward who builds the best editor experience atop shared compiler infrastructure.
Third-order effects
- If the pattern holds — languages and frameworks given away while Azure carries the monetization — platform loyalty migrates from operating systems to cloud services and developer productivity, a structural reversal of the 1990s-era Windows playbook.
- Widespread pickup of a single-day announcement suggests the industry now treats 'open source your core dev tech' as table stakes for big-platform credibility, raising the bar every incumbent vendor must clear with its own developer base.
The trend: Major platform vendors are opening their core development technologies to win developer mindshare, betting that revenue follows into cloud services rather than software licenses.