Microsoft today announced that it is furthering its commitment to cross-platform development with an expanded open source program for its .NET platform and additional support for operating systems outside of Microsoft Windows.

"With billions of devices in the market today, developers need tools that target many different form factors and platforms," said S. Somasegar, corporate vice president, Developer Division, Microsoft. "Through Visual Studio and .NET we are committed to delivering a comprehensive end-to-end solution for developers to build and manage applications across multiple devices and platforms."

After releasing several .NET libraries earlier this year to the open source community, Microsoft confirmed it would open source the full server .NET stack, making it available to developers via Github. The company also is expanding .NET to run on third-party platforms such as Linux and OS X and is working with the open source Mono project to ensure these cross-platform operations are ready for enterprise-level applications.

Microsoft-dotNET-logo
As part of its Connect() event, Microsoft also unveiled its next generation Visual Studio 2015 developer suite with expanded cross-platform support. Additionally, the Redmond company announced the immediate release of Visual Studio Community 2013 and Visual Studio 2013 Update 4.

This open source initiative is part of a broader campaign to support platforms outside of Windows and Windows Phone. The company now offers Office on the iPhone and iPad and is continuing its support for Apple's OS X platform. An updated version of Office for Mac is rumored for release sometime in 2015.

Top Rated Comments

macduke Avatar
144 months ago
So to recap, Microsoft is going open source and free with some of their products, Google is moving towards closed source with parts of Android, and Apple is now selling phablets faster than they can make them. Also my iPad is now as fast as a MacBook Air. What kind of alternate reality tech world have I suddenly stumbled into?
Score: 37 Votes (Like | Disagree)
flash84x Avatar
144 months ago
This seems huge, Nadella is killing it.
Score: 21 Votes (Like | Disagree)
talmy Avatar
144 months ago
.Net was suppose to be a cross platform language

In Microsoft-speak, "cross platform" means it will run on different versions of Windows. I'm not joking.
Score: 18 Votes (Like | Disagree)
mrfoof82 Avatar
144 months ago
This seems huge, Nadella is killing it.

.NET is actually a joy to work with. Being able to write apps in C# for OS X has been a dream for a lot of developers. It's a very lovely language and supporting framework.

I don't mind Objective-C. I like Swift (a lot). Though being able to use C# on OS X and have first-party support and tools from Microsoft would make me a very happy camper.
Score: 8 Votes (Like | Disagree)
thejadedmonkey Avatar
144 months ago
I wouldn't call this Microsoft going open source. This is them making it easier for themselves to release clients to other operating systems without having to create a completely native client. Also allowing people to leverage their technology in other software...the end game is that Microsoft is not counting on Windows anymore but are still very much a paid software company.

How much more "open source" than the MIT license can they possibly go?
Score: 6 Votes (Like | Disagree)
LogicalVue Avatar
144 months ago
Not what you think

It seems like most of you should have first read the actual MS announcement.

This announcement says that their server-side .NET framework will be eventually able to run on Linux and OS X. Linux matters for servers, but OS X is not all that relevant. This announcement has nothing to do with desktop GUI apps. It's all about the server and enterprise. Relevant quote:

Delivering on its promise to support cross-platform development, Microsoft is providing the full .NET server stack in open source, including ASP.NET, the .NET compiler, the .NET Core Runtime, Framework and Libraries, enabling developers to build with .NET across Windows, Mac or Linux. Through this implementation, Microsoft will work closely with the open source community, taking contributions for future improvements to .NET and will work through the .NET Foundation.

“A strong, open source, cross-platform CLR opens significant new options for building large server-based systems,” said Brian McCallister, chief technology officer, Groupon. “This significantly expands the choices developers have when finding the right tool to solve their problem. I’m very excited to have access to the quality virtual machine and tooling of the CLR without having to completely rework our production infrastructure in order to run it!”

There is also nothing in this announcement about allowing you to write .NET software using a Mac. MS does not have a Mac IDE and I don't expect them to create one either.

This is a good direction for Microsoft and .NET, but unless you are an enterprise software developer using .NET, this announcement will not affect you in any way.
Score: 4 Votes (Like | Disagree)

Popular Stories

iOS 26

When Will Apple Release iOS 26.2?

Monday December 1, 2025 4:37 pm PST by
We're getting closer to the launch of the final major iOS update of the year, with Apple set to release iOS 26.2 in December. We've had three betas so far and are expecting a fourth beta or a release candidate this week, so a launch could follow as soon as next week. Past Launch Dates Apple's past iOS x.2 updates from the last few years have all happened right around the middle of the...
maxresdefault

iPhone Fold: Launch, Pricing, and What to Expect From Apple's Foldable

Monday December 1, 2025 3:00 am PST by
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device. Subscribe to the MacRumors YouTube channel for more videos. Below, we've collated an updated set of key details that ...
ios 18 to ios 26 upgrade

Apple Pushes iPhone Users Still on iOS 18 to Upgrade to iOS 26

Tuesday December 2, 2025 11:09 am PST by
Apple is encouraging iPhone users who are still running iOS 18 to upgrade to iOS 26 by making the iOS 26 software upgrade option more prominent. Since iOS 26 launched in September, it has been displayed as an optional upgrade at the bottom of the Software Update interface in the Settings app. iOS 18 has been the default operating system option, and users running iOS 18 have seen iOS 18...
Sad Siri Feature

Apple AI Chief John Giannandrea Retiring After Siri Delays

Monday December 1, 2025 2:16 pm PST by
Apple AI chief John Giannandrea is stepping down from his position and retiring in spring 2026, Apple announced today. Giannandrea will serve as an advisor between now and 2026, with former Microsoft AI researcher Amar Subramanya set to take over as vice president of AI. Subramanya will report to Apple engineering chief Craig Federighi, and will lead Apple Foundation Models, ML research, and ...
Netflix Smaller 4

Netflix Kills Casting From Its Mobile App to Most Modern TVs

Monday December 1, 2025 4:36 am PST by
Netflix has quietly removed the ability to cast content from its mobile apps to most modern TVs and streaming devices, including newer Chromecast models and the Google TV Streamer. The change was first spotted by users on Reddit and confirmed in an updated Netflix support page (via Android Authority), which now states that the streaming service no longer supports casting from mobile devices...
Touchscreen MacBook Feature

Here Are the Four MacBooks Apple Is Expected to Launch Next Year

Monday December 1, 2025 5:00 am PST by
2026 could be a bumper year for Apple's Mac lineup, with the company expected to announce as many as four separate MacBook launches. Rumors suggest Apple will court both ends of the consumer spectrum, with more affordable options for students and feature-rich premium lines for users that seek the highest specifications from a laptop. Below is a breakdown of what we're expecting over the next ...
iphone 17 cyber

iPhone 17 Demand Is Breaking Apple's Sales Records

Tuesday December 2, 2025 9:44 am PST by
Apple's iPhone 17 lineup is selling well enough that Apple is on track to ship more than 247.4 million total iPhones in 2025, according to a new report from IDC. Total 2025 shipments are forecast to grow 6.1 percent year over year due to iPhone 17 demand and increased sales in China, a major market for Apple. Overall worldwide smartphone shipments across Android and iOS are forecast to...
Cyber Week Deals 2025

Best Cyber Week Apple Deals Include Big Discounts on AirPods, Apple Watch, and More

Sunday November 30, 2025 7:33 am PST by
Cyber Week is here, and you can find popular Apple products like AirPods, iPad, Apple Watch, and more at all-time low prices. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment, which helps us keep the site running. Specifically,...
iOS 26

What to Expect From Apple This December: iOS 26.3 Beta, Replay 2025, and More

Monday December 1, 2025 8:40 am PST by
The calendar has turned to December, and the quieter year-end holiday season is now upon us. Nevertheless, we can still expect a few things from Apple this month. Apple previously announced that iOS 26.2 will be released to the general public in December, and we can expect corresponding updates to be released as well, including iPadOS 26.2, macOS 26.2, watchOS 26.2, tvOS 26.2, and visionOS...
iOS 26

Apple Seeds iOS 26.2 and iPadOS 26.2 Release Candidates to Developers and Public Beta Testers

Wednesday December 3, 2025 10:33 am PST by
Apple today seeded the release candidate versions of upcoming iOS 26.2 and iPadOS 26.2 updates to developers and public beta testers, with the software coming two weeks after Apple seeded the third betas. The release candidates represent the final versions of iOS 26.2 and iPadOS 26.2 that will be provided to the public if no further bugs are found during this final week of testing....