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Microsoft and Open Source

This is an unofficial timeline of Microsoft's transition towards open source.

This project is not endorsed by Microsoft or any company or project mentioned here.

This listing could not possibly be complete, so please open PRs with any additions.



  • Microsoft begins experimenting with 'shared source', including SSCLI, the core of .NET


  • WiX, the first project from Microsoft under an OSS approved license, is released
  • Begins cross-licensing software patents with Linux vendors


  • F# released under the Apache 2.0 license


  • CodePlex announced
  • Ports PHP to Windows, upstreams code under PHP license
  • Partners with Novell to improve open source interoperability


  • Open Source Initiative approves the Microsoft Public License (MS-PL) and Microsoft Reciprocal License (MS-RL)
  • Provides access to Windows NT kernel source for research to universities
  • Open sources IronRuby and IronPython under Microsoft Public License
  • Open sources xunit under Microsoft Public License
  • Reaches agreement with EU to reduce costs of licensing patents and specifications
  • Scheduled to exit US DOJ antitrust oversight, voluntarily agrees to extended oversight


  • Forms Open Web Foundation with Google, Facebook, Sun, IBM, Apache, and others
  • Joins Apache Software Foundation
  • Releases source for Singularity, an experimental OS to CodePlex
  • Begins distributing the open source jQuery JavaScript library with Visual Studio
  • Acquires Powerset, it's first open source acquisition, upstreams code from HBase to Apache Hadoop
  • Open sources Manage Extensibility Framework (MEF) under Microsoft Public License, one of the first bits of the .NET framework to be open sourced


  • Begins contributing to Linux kernel
  • Forms independent CodePlex Foundation, later known as Outercurve Foundation to promote open source
  • Open sources ASP.NET MVC under the Microsoft Public License
  • Apologizes after download is found to have GPL code, properly open sources download
  • Promises not to enforce patents against open source implementations of C#, e.g. Mono
  • Settles a dispute with TomTom over FAT32 software patents, avoiding further conflict with open source
  • Reaches agreement with EU to provide users a choice of web browsers on Windows installation
  • Platform Strategy Group begins an internal push for embracing open source
  • "Burning the Ships: Transforming Your Company's Culture Through Intellectual Property Strategy" is published on Microsoft's embrace of open collaboration
  • 📺 Microsoft's Ray Ozzie on IP and Open Source
  • 📰 "Has Microsoft lost its war on open source?" InfoWorld



  • Acquires Skype, maintains Linux client
  • Begins contributing code to Samba
  • Exits antitrust oversight by US DOJ
  • Ports Node.js to Windows, upstreams code under Apache 2.0
  • "Microsoft Embraces Elephant of Open Source" Wired


  • Azure begins hosting Linux virtual machines
  • Codeplex supports git
  • Begins contributing to git and collaborates with GitHub on LibGit2
  • Ports Apache Hadoop to Windows, upstreams code under MIT
  • Open sources ASP.NET, MCV, Razor, and Web API under Apache 2.0
  • Forms Microsoft Open Technologies, Inc.
  • Releases TypeScript under Apache 2.0, first Microsoft project on GitHub
  • Canonical closes Ubuntu bug #1
  • 📺 Microsoft, The Cloud and Open Source
  • 📰 "Microsoft opens up" O'Reily


  • Steve Ballmer resigns
  • VM Depot announced, community-driven repository of Linux and BSD virtual machines for Azure
  • Microsoft challenges broad US warrant for overseas e-mails and helps create a new law improving e-mail privacy
  • Releases Coding4Fun Toolkit, a set of open source components for building Windows Phone applications
  • xunit transferred to Outercurve Foundation, relicensed under Apache 2.0
  • 📰 "Microsoft's Open Source Company Is a Year Old. But What Is It?" Wired


  • Satya Nadella appointed CEO
  • The full .NET stack, Microsoft's flagship development toolkit, is open sourced and contributed to .NET Foundation
  • Creates official GitHub prescence
  • Implements AllJoyn support in Windows, contributes code upstream
  • Releases Wireless Display Adapter, first hardware device to use embedded Linux
  • Contributes to OpenJDK
  • 📺 "Microsoft loves Linux." - Satya Nadella
  • 📰 "More open-source at Microsoft? You'd better believe it" VentureBeat


  • Visual Studio Code released, releases Linux build
  • Co-founds Node.js Foundation
  • Joins R Foundation
  • Forms Open Source Programs Office, tasked with enabling and normalizing open source across the company
  • Open sources Matter Center, Microsoft's legal practice management software
  • Open sources Chakra, legacy Microsoft Edge’s JavaScript engine
  • 📰 "How Open Source Is Shaping Microsoft's Future" RedmondMag


  • Windows Subsystem for Linux announced in partnership with Canonical
  • Joins Linux Foundation
  • Joins Eclipse Foundation
  • Open sources PowerShell, releases Linux build
  • Begins porting Sysinternals to Linux
  • Acquires Xamarin, relicenses Mono under MIT
  • Acquires LinkedIn, maintains Apache Kafka
  • SQL Server released for Linux
  • Begins hosting Linux Foundation courses on edX
  • SONiC released, based on Debian GNU/Linux
  • Begins opening Reactors worldwide for use by entrepreneurs and open source communities
  • "The company has become an enthusiastic supporter of Linux and of open source and a very active member of many important projects." - Jim Zemlin, Executive Director of The Linux Foundation
  • 📺 Open Source at Microsoft at Thailand Developer Day 2016
  • 📰 "Why Microsoft is turning into an open-source company" ZDNet


  • Satya Nadella releases "Hit Refresh: The Quest to Rediscover Microsoft's Soul and Imagine a Better Future for Everyone" describing his vision for an open and collaborative Microsoft
  • Joins Open Source Initiative
  • Joins Cloud Native Computing Foundation
  • Joins MariaDB Foundation
  • Acquires Deis
  • Open sources Git Virtual File System (GVFS), the work done moving Windows to git
  • Opens Microsoft Store to open source applications
  • Better privacy controls, privacy dashboard, and diagnostic data transparency introduced in Windows
  • Announces Linux development with C++ in Visual Studio
  • Gives keynote at Open Source Summit North America
  • Moves Windows development to git
  • Microsoft shuts down CodePlex (announcement)
  • 📺 Microsoft Loves Open Source: Becoming The Largest Contributor at GitHub Universe 2017
  • 📰 "How Microsoft Is Shifting Focus to Open Source" The New Stack


  • Joins Open Innovation Network, cross-licenses 60,000 patents with open source community
  • Acquires GitHub
  • "We are all in on open source." - Satya Nadella
  • GitHub Actions is released, providing free CI/CD for open source projects
  • Windows Subsystem for Linux 2 announced powered by Linux kernel
  • Begins using Citus and PostgreSQL on Ubuntu to analyze telemetry from Windows test builds on employee devices
  • PowerShell released as a snap
  • OpenSSH included in Windows
  • Provides official Ubuntu desktop images in Hyper-V on Windows
  • Beings collaborating with Canonical on cloudinit
  • Shifts their mobile application strategy to Android, begins contributing to Android developer ecosystem
  • Windows Calculator released as open source
  • 📺 Building an Open Source Software Culture at Microsoft at Open Source Summit Europe
  • 📰 "Microsoft may be the world's largest open source contributor" TechRepublic


  • Visual Studio Code released as a snap
  • GitHub announces GitHub Sponsors, lowers prices
  • Edge browser released based on open source Chromium
  • Linux surpasses Windows usage on Azure
  • Begins adopting open source-style collaboration internally
  • Teams released for Linux
  • Acquires Citus Data, maintains open source project
  • Joins OpenChain
  • Admitted to Linux-distros security mailing list
  • Creates Open Application Model with Alibaba Cloud as a Open Web Foundation project
  • Creates Kubernetes-based Event-Driven Autoscaling (KEDA) with Red Hat as an application autoscaler for Kubernetes
  • Releases new Windows Terminal and PowerToys as open source
  • Published exFAT as open specification, contributes patents to OIN, and upstreams driver to Linux kernel
  • Stores all public GitHub repos for 1,000 years in Svalbard, Norway
  • Joins Unified Patents Open Source Zone to defend open source from patent trolls
  • Announces Android-based smartphone, Surface Duo, with a Linux kernel
  • Announces Microsoft Defender for Linux
  • Open sources SPTAG, a crucial search algorithm used by Microsoft
  • Open sources SandDance, a data visualization tool
  • Open sources the Microsoft C++ Standard Library
  • Open sources Interpret ML
  • Open sources Quantum Development Kit, a quantum computing SDK
  • Satya Nadella speaks at Red Hat Summit
  • Richard Stallman speaks at Microsoft, states "we should not maintain a burning grudge over actions that ended years ago"
  • Linux Torvalds quoted at Linux Plumbers Conference as saying Microsoft "have changed"
  • JS Foundation and Node.js Foundation merge to form OpenJS Foundation, Microsoft contributes Electron to OpenJS Foundation
  • 📺 Scott Hanselman gives keynote at NDC London laying out Microsoft's open source vision
  • 📰 "Microsoft: The open source company" Ars Technica


  • Acquires npm, the Node package manager
  • Hosts WSLConf, the first conference dedicated to WSL
  • Microsoft president Brad Smith admits Microsoft was wrong about open source
  • Microsoft Edge browser on Linux seen at Microsoft Build
  • Push improvements to Chromium upstream
  • Releases open source Windows Package Manager 'winget'
  • Releases .NET for Apache Spark
  • Open sources a dataset to help fight COVID-19-related cybersecurity threats
  • Open sources Java extension for SQL Server
  • Open sources MSQuic, a Windows NT kernel library for QUIC
  • Open sources Petridish, a neural architecture search algorithm for deep learning
  • Open sources Project Rocket, a software stack to perform live video analysis by AI/ML
  • Open sources Project Bonsai, a machine teaching service
  • Open sources Application Inspector, cross-platform source code security analyzer
  • Open sources TensorWatch, a debugging tool for AI and deep learning
  • Open sources Project Verona, a memory-safe research language
  • Open sources CLon12 and GLon12 projects, providing OpenCL and OpenGL support on Windows, based on the Mesa project
  • Collaborates with Tigera to open source Calico for Windows, enabling Windows container network policy support
  • Open sources ONNX Runtime, a cross-platform machine learning runtime used by Office 365, Visual Studio, and Bing
  • Open sources Akri, a project that extends Kubernetes to leaf devices
  • Open sources Fluid Framework, a set of libraries for enabling low-latency collaborative data sharing
  • Open sources Project OneFuzz, an open source developer tool to find and fix bugs at scale
  • Open sources SmartNoise Platform, powered by OpenDP, which safeguards the privacy of individuals while making useful data available for research
  • Open sources ION, a public permissionless decentralized network identifier based on blockchain
  • Upstreams improvements to Mesa's core support for OpenCL and SPIR-V
  • Upstreams open source improvements to QNNX natural language model
  • Releases Microsoft Edge for Linux in developer preview
  • Publishes CBL-Delridge, a custom Debian derivative for internal use
  • Publishes CBL-Mariner, a custom Linux From Scratch-style distribution powered by rpm packages for internal use
  • Linux-based Azure Sphere OS released for connecting devices to the Azure Sphere Security Service
  • Participates extensively at the X.Org Conference, XDC
  • Launches Project Freta, a cloud-based service that provides automated full-system volatile memory inspection of Linux systems
  • Partners with Canonical to provide Ubuntu Pro and Charmed Kubernetes on Azure Arc
  • Announces Python for Excel
  • Kubernetes-based Event-Driven Autoscaling (KEDA) joins CNCF as a sandbox project (announcement)
  • Ad features Ubuntu on Surface Book 3
  • 📰 "Microsoft’s romance with open source software is on display at Build 2020" Ars Technica



Known Open Source Collaborations

  • SUSE
  • Red Hat
  • Canonical
  • Collabora
  • IBM
  • Oracle
  • Google
  • Chef
  • Puppet
  • Redis Labs
  • Elastic
  • Samsung
  • Cloudera
  • Docker
  • Nokia
  • HashiCorp
  • PostgreSQL
  • Kali Linux
  • Whitewater Foundry
  • Allianz
  • React
  • Flutter
  • HashiCorp
  • Nvidia
  • BMW
  • Apache Cassandra
  • Apache Kafka
  • Apache Hadoop
  • Apache Spark
  • Linux Foundation
  • Cloud Native Computing Foundation
  • Eclipse Foundation
  • OpenDaylight
  • Open Container Initiative
  • R Consortium
  • F# Foundatoin
  • .NET Foundation
  • Open API Initiative
  • Confidential Computing Consortium
  • OpenChain
  • TODO Group
  • Open Source Initiative
  • Apache Software Foundation
  • iZootoo
  • StorSimple
  • Grafana
  • Tigera

Select Open Source Projects

The list below is incomplete. current lists 1,155 open source projects at Microsoft and it would not be possible to curate them all here. Click here for access to find them all.

Here is a list of selected projects:

Dev Tools


Web Dev Tools

  • Playwright - Node library to automate Chromium, Firefox and WebKit with a single API
  • Blazor




  • Azure CLI
  • Azure Arc
  • Azure Databricks
  • Azure Linux virtual machines
  • Azure Linux containers
  • Azure-tuned Linux kernel
  • Azure Spring Cloud
  • Azure DevOps
  • Azure HDinsight
  • Open Enclave SDK - A hardware-agnostic open source library for developing applications that utilize hardware enclaves.




  • WorldWide Telescope - A visualization environment that brings together imagery from the world's best ground- and space-based telescopes
  • Project Mu - The UEFI core used in Microsoft Surface and Hyper-V

Programming Languages

  • TypeScript - Programming language similar to JavaScript, among the most popular on GitHub
  • Bosque - An experiment in regularized design for a machine assisted rapid and reliable software development lifecycle
  • Verona - Research programming language for concurrent ownership
  • SPTAG - A library for fast approximate nearest neighbor search
  • P - A language for asynchronous event-driven programming

More Open Source at Microsoft

Historic Open Source Contributions

  • Linux® is a registered trademark of Linus Torvalds in the United States and/or other countries. *
  • Windows®, Windows 10®, Microsoft®, Visual Studio®, Azure®, Build, and PowerShell® are trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries. * **
  • Ubuntu® and Canonical® are registered trademark of Canonical Limited in the United States and/or other countries. *
  • SUSE® and SUSE Linux Enterprise® are registered trademarks of SUSE in the United States and/or other countries. *
  • Red Hat® is a trademark or registered trademark of Red Hat, Inc. in the United States and/or other countries. *
  • Debian® is a registered trademark of Software in the Public Interest, Inc. in the United States and/or other countries. *
  • Kali Linux® and Offensive Security® are registered trademarks of OffSec Services, Ltd. *
  • Docker® and Docker Hub® are registered trademarks of Docker, Inc. *
  • Oracle and Oracle Linux are trademarks or registered trademarks of Oracle, Inc. *

All other trademarks mentioned herein are the property of their respective owners and may be registered in the United States and/or other countries.


An unofficial timeline of Microsoft's transition towards open source








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