Inner Source: Bringing Open Source Culture Inside Your Organization

Over the years of maintaining open source libraries and running large data science teams in complex conglomerates, I’ve noticed something fascinating: the practices that make open source development successful can be incredibly powerful inside organizations too. This approach, known as inner source, brings the collaborative spirit and efficiency of open source development into corporate environments.

What is Inner Source?

At its core, inner source is about applying open source development practices and culture within the boundaries of an organization. Instead of teams working in isolation, they collaborate on shared codebases, contribute to each other’s projects, and build a community around internal tools and libraries.

Think of it like having your own internal GitHub ecosystem, where different teams can discover, use, and contribute to libraries developed across the organization. The key difference? Everything stays within your company’s walls.

Why Inner Source Matters

I’ve seen firsthand how siloed development can lead to:

• Multiple teams solving the same problems differently
• Valuable code buried in team-specific repositories
• Knowledge trapped within individual teams
• Reinvention of wheels (so many wheels!)

Inner source addresses these issues by creating a culture of collaboration and code sharing. When done right, it can:

• Reduce duplication of effort
• Spread knowledge across teams
• Improve code quality through peer review
• Speed up development through code reuse
• Build stronger engineering culture

Common Misconceptions

“It’s Just Internal Open Source”

While inner source draws inspiration from open source, it’s not just about slapping an open source license on internal code. The dynamics are different when everyone’s getting paid by the same company. You need different incentives, different governance models, and different approaches to contribution.

“It Will Slow Us Down”

I hear this one a lot. “We can’t wait for other teams to review our code!” But that’s missing the point. Inner source isn’t about forcing every change through a complex review process. It’s about making collaboration possible when it makes sense.

“Our Code Isn’t Good Enough”

Perfect is the enemy of good. Your internal libraries don’t need to be pristine to be shared. What matters is that they’re useful and that you’re open to improving them over time.

Key Elements of Inner Source

1. Discoverability

Teams need to be able to find existing libraries. This might mean:

• Internal package registries
• Documentation hubs
• Library catalogs
• Code search tools

2. Clear Ownership

Every shared library needs clear owners who:

• Review contributions
• Maintain documentation
• Guide development
• Support users

3. Contribution Process

Make it easy for teams to contribute by having:

• Clear contribution guidelines
• Standard development practices
• Efficient review processes
• Good documentation

4. Support Model

Define how library maintenance works:

• Who handles bug fixes?
• How are feature requests managed?
• What’s the SLA for critical issues?
• How is support time allocated?

Getting Started

Starting small is key. Here’s a practical approach:

1. Identify Candidates: Look for libraries that multiple teams could use
2. Build Infrastructure: Set up the basic tools needed for collaboration
3. Start with Champions: Find enthusiastic early adopters
4. Document Success: Track and share wins to build momentum
5. Iterate and Improve: Adjust based on feedback and results

The Cultural Shift

The biggest challenge in adopting inner source isn’t technical - it’s cultural. You’re asking teams to:

• Share their code
• Accept external contributions
• Think beyond their immediate needs
• Invest in documentation
• Collaborate across organizational boundaries

This requires support from leadership and a clear demonstration of value to all stakeholders.

Next Steps

In the next post in this series, we’ll dive deep into building your internal library developer community - the human side of inner source. We’ll look at incentive structures, recognition systems, and practical ways to foster collaboration.

Remember: inner source isn’t about copying open source exactly - it’s about taking the best parts of open source development and adapting them to work within your organization’s unique context.