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The Apache Project Maturity Model provides a suggested framework for evaluating the overall maturity of an Apache project community and the codebase that it maintains. While this model is specific to Apache projects (i.e. hosted at the ASF) many of these factors are important for any open source project.
The goal of this maturity model is to describe how Apache projects operate, in a concise and high-level way, and to provide a basic framework that projects may choose to use to evaluate themselves.
It is meant to be usable outside of Apache as well, for projects that might want to adopt some or all of these principles. Projects that envision moving to Apache at some point might start working towards this to prepare for their move.
It does not describe all the details of how our projects operate, but aims to capture the invariants of Apache projects and point to additional information where needed. To keep the main model as concise as possible we use footnotes for anything that’s not part of the core model.
Contrary to other maturity models, we do not define staged partial compliance levels. A mature Apache project complies with all the elements of this model, and other projects are welcome to pick and choose the elements that suit their goals.
Note that we try to avoid using the word “must” below. The model describes the state of a mature project, as opposed to a set of rules.
Projects which incubate at Apache might not fit into all the parts of this model, however a major goal of incubation is to bring the project’s community closer to it.
Questions and feedback about this model are welcome on the comdev mailing list.
The Apache Project Maturity Model
Each item in the model has a unique ID to allow them to be easily referenced elsewhere.
The project produces Open Source software, for distribution to the public at no charge.
The project's code is easily discoverable and publicly accessible.
The code can be built in a reproducible way using widely available standard tools.
The full history of the project's code is available via a source code
control system, in a way that allows any released version to be
The provenance of each line of code is established via the source code control system, in a reliable way based on strong authentication of the
committer. When third-party contributions are committed, commit messages provide reliable information about the code provenance.
Licenses and Copyright
- The code is released under the Apache License, version 2.0.
Libraries that are mandatory dependencies of the project's code do not create more restrictions than the Apache License does.
The libraries mentioned in LC20 are available as Open Source software.
- Committers are bound by an Individual Contributor Agreement (the "Apache iCLA") that
defines which code they are allowed to commit and how they need to
identify code that is not their own.
The copyright ownership of everything that the project produces is clearly defined and documented.
- Releases consist of source code, distributed using standard and open archive
formats that are expected to stay readable in the long term.
Releases are approved by the project's PMC (see CS10), in order to make them an act of the Foundation.
Releases are signed and/or distributed along with digests that can be reliably used to validate the downloaded archives.
- Convenience binaries can be distributed alongside source code but they are not Apache Releases -- they are just a
convenience provided with no guarantee.
- The release process is documented and repeatable to the extent that
someone new to the project is able to independently generate the complete
set of artifacts required for a release.
project is open and honest about the quality of its code. Various levels
of quality and maturity for various modules are natural and acceptable
as long as they are clearly communicated.
The project puts a very high priority on producing secure software.
The project provides a well-documented, secure and private channel to report security issues, along with a documented way of responding to them.
- The project puts a high priority on backwards compatibility and aims to document any incompatible changes and provide tools and documentation to help users transition to new features.
The project strives to respond to documented bug reports in a timely manner.
The project has a well-known homepage that points to all the information required to operate according to this maturity model.
The community welcomes contributions from anyone who acts in good faith and
in a respectful manner and adds value to the project.
Contributions include not only source code, but also documentation, constructive bug
reports, constructive discussions, marketing and generally anything that
adds value to the project.
The community strives to be meritocratic and over time aims to give more rights and
responsibilities to contributors who add value to the project.
The way in which contributors can be granted more rights such as commit
access or decision power is clearly documented and is the same for all
The community operates based on consensus of its members (see CS10) who
have decision power. Dictators, benevolent or not, are not welcome in
The project strives to answer user questions in a timely manner.
project maintains a public list of its contributors who have decision
power -- the project's PMC (Project Management Committee) consists of
Decisions are made by consensus among PMC members
and are documented on the project's main communications channel.
Community opinions are taken into account but the PMC has the final word
Documented voting rules are used to build consensus when discussion is not sufficient.
Apache projects, vetoes are only valid for code commits and are
justified by a technical explanation, as per the Apache voting rules
defined in CS30.
All "important" discussions happen asynchronously in written form on the
project's main communications channel. Offline, face-to-face or private discussions
that affect the project are also documented on that channel.
The project is independent from any corporate or organizational influence.
- Contributors act as themselves as opposed to representatives of a corporation or organization.
How To Use The Apache Project Maturity Model
Remember: This model is a suggested guide; it is not a requirements document. The model shows what generally good behaviors in an Apache project look like.
So far, inside the ASF this model has been used mostly for self-assessment of podlings preparing their graduation
from the Apache Incubator.
It might be useful for top-level ASF projects to regularly assess their maturity based on this model, but this is not a requirement at this time.
Here are a few self-assessment examples:
Other Open Source Project Models
See https://s.apache.org/apache_maturity_model for the discussions that led to this. And thanks to the many people who provided input! The links below are both inspirations for our model above, and are some of the other ways that FOSS project participants have tried to quantify ways to measure open source projects.
Status / Document Version
v 1.0, February 2015, defined by consensus by Apache Community Development project.
v 1.1, October 2016 added RE50.
v 1.2, February 2018, reworked the “how to use” section with more links to self-assessments.
See the svn revision history of this document for more details and other minor changes.
"For distribution to the public at no charge" is straight from the from the ASF Bylaws at https://apache.org/foundation/bylaws.html.
See also LC40.
It's ok for platforms (like a runtime used to execute our code) to have different licenses as long as they don't impose reciprocal licensing on
what we are distributing.
https://apache.org/legal/resolved.html has information about acceptable licenses for third-party dependencies
In Apache projects, the ASF owns the copyright for the collective work,
i.e. the project's releases. Contributors retain copyright on their
contributions but grant the ASF a perpetual copyright license for them.
See https://www.apache.org/legal/release-policy.html for more info on Apache releases
The required level of security depends on the software's intended uses, of course. Expectations should be clearly documented.
Apache projects can just point to https://www.apache.org/security/ or use their own security contacts page, which should also point to that.
In Apache projects, "consensus" means widespread agreement among people who have decision power. It does not necessarily mean "unanimity".
For Apache projects, https://www.apache.org/foundation/voting.html defines the voting rules.
Apache projects have a private mailing list that their PMC is expected to use
only when really needed. The private list is typically used for
discussions about people, for example to discuss and to vote on PMC
Independence can be understood as basing the project's decisions on the open
discussions that happen on the project's main communications channel,
with no hidden agendas.