InnerSource principles

Every company, team, project, and individual is different. Because of that fact, the exact way that the concept of InnerSource works will vary from one situation to another. At its core, however, are four principles that form the bedrock of any successful instance of InnerSource. These principles have inspiration in successful open source projects and are required in order for InnerSource to achieve the benefits described earlier.

The principles are:

  • Openness

  • Transparency

  • Prioritized Mentorship

  • Voluntary Code Contribution

Let’s take a look at each of these principles in more detail.


The configuration of an open project enables frictionless contributing. Projects should be discoverable and well-documented through and files within the root of the repo. Anyone within an organization should be able to find a desired project and ramp up without an inordinate amount of direct guidance from host team members. Host team contact information should be prevalent with as many channels as makes sense for the project. Host team intentions to accept InnerSource contributions to their project should be shared through relevant organization channels to raise awareness. Particularly in smaller settings you may want to establish a regular "broadcast" on the InnerSource work your team is doing. In larger settings, however, such broadcast may create a lot of noise, and it may be more appropriate to make sure the project is discoverable in a easy-to-use tool. Remember, the goal is awareness use the appropriate channels that work in YOUR company.

By no means is the above an exhaustive list. Project openness will typically be directly related to how successful a project is in terms of InnerSource. The more open it is, the fewer barriers are put in place for prospective contributors. The less open it is, the more difficult it becomes for anyone to contribute.


In order for guest teams to be able to contribute meaningfully to a project, the host team must be transparent. This means that guest teams should be able to have an understanding of:

  • The project/repo and its direction

  • Outstanding feature requirements

  • Progress on feature requirements

  • Decision making of the host team

When possible, the above should be communicated clearly and in detail, from teams' internal definitions of items to special-case scenarios specific to the project. This communication should be done in a manner that can be easily queried and understood to those that are not part of the core team.

Prioritized Mentorship

Mentorship from host team to guest team via trusted committers is a key aspect of InnerSource. Contributors on guest teams are upleveled so that they understand enough about the host team’s project/repo to change it successfully. In the process of doing so, they come to better understand the host team’s software system as a general consumer and ambassador for the project/software. This individual contributor can, over time and with experience, take on a broader role in the project as a trusted committer.

It’s critical that this mentorship for contributors is Prioritized by the host team. The host team should strive to make time to mentor guest team contributors at the time that the contributor needs it as opposed to when it’s convenient to the host team. At times it may be a culture change for engineers on the host team to spend time helping others to code rather than just coding themselves. This mentorship is valuable to both the individual contributor and the host, and it is worth doing well. It proves to be mutually beneficial in the long run. By improving the code, the contributor forges or improves relationships within an organization that may not have existed otherwise. Open source readily recognizes this point and considers it as an honor to achieve trusted committer status on a project.

Voluntary Code Contribution

The first word Voluntary means that engagement in InnerSource from both the guest and host teams occurs of their own free will. The guest team voluntarily donates code to the host team and the host team voluntarily accepts it. This opt-in nature means that each team needs to be certain that their involvement adds value to the others' objectives. Never is a host team required to accept a contribution that isn’t in ultimate alignment with their overall mission. Never is a guest team required to submit a contribution that doesn’t ultimately further their own mission and priorities.

The word Code emphasizes that the collaboration between guest and host goes all the way to the code. Guest involvement in opening issues, updating requirements, fixing docs, etc. is good, but collaboration needs to reach as far as submitting code to achieve all of the benefits that we’ve discussed.