The Rise of InnerSource and Impactful Open Collaboration

For more than 20 years, I have worked with developers and developer communities, working with the latest available technology. About five years ago, I realized that successful digital transformation relied more on psychology and culture as it does on the excellence of the underlying technology. The question I started to ask myself was: How can organizations create an environment where individuals are motivated to work together to innovate organically? 

I found one answer in InnerSource. 

The Rise of InnerSource  

The term InnerSource was first coined by Tim O’Reilly in 2000 to describe the use of open source development techniques within a corporation to develop proprietary code. It promotes the principles of openness and transparency inside a company’s firewall.  

With InnerSource, you can view all your organization’s code, use what is useful, and contribute any changes that you need for your contextTrusted committers then decide whether to incorporate those changes into the original codebase. It replicates how the open source community works, except the resulting source code stays within the confines of the company. A brilliant way to get used to open source culture in a safe environment. 

Although it was first championed as a step on the path to open source, it turns out that InnerSource  also breaks down silos, reduces bottle necks and accelerates innovation. Indeed, because the latest generation of developers have grown up in a world of open sourceand the related levels of agency and autonomy, adopting InnerSource can help create a working environment that will make it easier to find and retain today’s most talented developers. 

An Idea Whose Time Has Come 

Although first coined back in the early noughties, the idea of InnerSource really started to gain momentum in 2015, when long term open source advocate Danese Cooper began to advocate for the use of InnerSource. This coincided with increasing interest in open source in corporate enterprises. Danese Cooper had been hired to head up PayPal’s open source programs, but she quickly realized that PayPal needed to learn a lot about open collaboration before they could successfully participate in the open source ecosystem. In 2015 she gave a keynote at the annual OSCON conference and announced that PayPal was to focus on building InnerSource skills as part of their journey towards open source development. In that talk, she also announced the formation of the InnerSource Commons, a community of practice for individuals with the goal of creating and sharing knowledge about InnerSource. 

Since then, InnerSource has been adopted by tens of thousands of developers, across all industries from big tech to banking, manufacturing, and retail, in all corners of the globe.  

Why InnerSource? 

As mentioned above, InnerSource emerged as a way to get corporate developers ready to collaborate effectively in the open source ecosystem. In fact, organizations like Comcast have declared that no internal project can be open sourced unless it has first built an InnerSource community within Comcast. This ensures that the development team knows how to build a sustainable community of contributors before they release the code under an open source license.  

But open source readiness is just one reason why so many companies are exploring InnerSource. Listed below are some of the other benefits InnerSource can deliver. 

Permission-less Innovation 

Every article you read about “future of work” today will tell you that effective collaboration is key to successful innovation and staying relevant in our fast-moving world. Unfortunately, the reality is that most organizations suffer from silos and a culture of excessive ownership that result in lots of re-inventing wheels and system friction when it comes to internal collaborationInnerSource allows developers to “scratch their own itch” or make changes they need in their organization’s software outside their normal sphere of influence, without requiring the permission of the original code creators. This removes a huge amount of innovation bottlenecks in an organization. 

Code Re-use 

It inot uncommon for an organization to have multiple implementations of the same technology. The worst scenario I heard of recently was an organization who had realized they had 35+ implementations of the same system which they were trying to bring together in the organizationThe “not invented here” syndrome is a plague that does not just influence decisions to buy in technology from outside, it can often result in internal groups wasting resources and choosing to build something from scratch rather than attempt to re-use another group’s code. 

InnerSource focuses on increasing code reuse within an organization. Tracking cross-group contributions is a common InnerSource KPIs and code re-use can result in big savings. At one FINOS meeting, Accenture reported that they had saved Deutsche Bank €12m due to code re-use utilizing the power of InnerSource. 

Accelerated Development 

Being able to re-use code and assemble pre-built components has a direct impact on how quickly you can produce working code. However, it is only one aspect of how InnerSource can speed up development.  

In a recent article on “Developer Velocity” McKinsey sought to identify how excellence in software development fuels better business performance. They showed that companies in the top quartile of their Developer Velocity Index outperform others in the market by four to five times. Alongside open source adoption, open source culture, or InnerSource, emerged as the biggest differentiator among top quartile performers.  

Happier Developers 

Finally, and perhaps most importantly, InnerSource just makes developers happier. The latest generation of developers expect agency and autonomy. With InnerSource, developers have the autonomy to review, use and modify code as required from anywhere in the company without seeking permission. It provides the opportunity for developers to reach out and build relationships outside their silos. It promotes knowledge sharing. It is how developers today prefer to work! 

Getting Started with InnerSource 

InnerSource is a path to organic innovation within organizations. It creates an open culture of collaboration that delivers faster innovation alongside happier developers. So, the question now becomes: How do you get started with InnerSource? 

The good news is that you are not alone in answering that question. 

The InnerSource Commons has continued to grow and scale alongside the growth of InnerSource. It now has over 900 individuals from over 350 organizations who have volunteered their time to produce resources such as books, learning paths and research to help companies on their InnerSource journey. I began to work with the Commons in early 2019 and can say it is a warm and welcoming group of people. If you are interested in learning more about InnerSource, there is no better way to get started than to drop in to have a chat and virtual coffee with one of the community members. Join us at to find out more. 


Clare Dillon 2019 899x1024 1Clare Dillon has spent over 20 years working with developers and developer communities. She spent 8 years as part of the Microsoft Ireland Leadership Team, heading up their Developer Evangelism & Experience Group. She is a relatively new convert to the open source way but is all in now. Alongside her current work with InnerSource Commons, Clare works with to support the establishment of University and Government Open Source Program Offices and OSPOs++ globally that can collaborate to implement public policy and trustworthy public services. Clare has served on the boards of Ireland’s National Digital Research Centre, the Irish Internet Association and on the Industry, Guidance Boards of the Irish Centre for Cloud Computing and Commerce and the Technology Ireland Innovation Forum. She frequently speaks at international conferences and corporate events on topics relating to the future of work, innovation trends and digital ethics.