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 projects of the Apache Software Foundation (ASF), many of these factors apply to any open source project.

Overview

The goals of this maturity model are 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 usable outside of the ASF as well, for projects that might want to adopt some or all of these principles. Projects that envision moving to the ASF 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 be 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 adopt 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 the ASF 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.

We welcome questions and feedback about this model on the comdev mailing list.

The Apache Project Maturity Model

Each item in the model has a unique ID to allow it to be easily referenced elsewhere.

Code

CD10
The project produces Open Source software for distribution to the public, at no charge. 1
CD20
Anyone can easily discover and access the project's code.
CD30
Anyone using standard, widely-available tools, can build the code in a reproducible way.
CD40
The full history of the project's code is available via a source code control system, in a way that allows anyone to recreate any released version.
CD50
The source code control system establishes the provenance of each line of code in a reliable way, based on strong authentication of the committer. When third parties contribute code, commit messages provide reliable information about the code provenance. 2
LC10
The Apache License, version 2.0, covers the released code.
LC20
Libraries that are mandatory dependencies of the project's code do not create more restrictions than the Apache License does. 3 4
LC30
The libraries mentioned in LC20 are available as Open Source software.
LC40
Committers are bound by an Individual Contributor Agreement (the "Apache iCLA") that defines which code they may commit and how they need to identify code that is not their own.
LC50
The project clearly defines and documents the copyright ownership of everything that the project produces. 5

Releases

RE10
Releases consist of source code, distributed using standard and open archive formats that are expected to stay readable in the long term. 6
RE20
The project's PMC (Project Management Committee, see CS10) approves each software release in order to make the release an act of the Foundation.
RE30
Releases are signed and/or distributed along with digests that anyone can reliably use to validate the downloaded archives.
RE40
The project can distribute convenience binaries alongside source code, but they are not Apache Releases, they are provided with no guarantee.
RE50
The project documents a repeatable release process so that someone new to the project can independently generate the complete set of artifacts required for a release.

Quality

QU10
The 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.
QU20
The project puts a very high priority on producing secure software. 7
QU30
The project provides a well-documented, secure and private channel to report security issues, along with a documented way of responding to them. 8
QU40
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.
QU50
The project strives to respond to documented bug reports in a timely manner.

Community

CO10
The project has a well-known homepage that points to all the information required to operate according to this maturity model.
CO20
The community welcomes contributions from anyone who acts in good faith and in a respectful manner, and who adds value to the project.
CO30
Contributions include source code, documentation, constructive bug reports, constructive discussions, marketing and generally anything that adds value to the project.
CO40
The community strives to be meritocratic and gives more rights and responsibilities to contributors who, over time, add value to the project.
CO50
The project documents how contributors can earn more rights such as commit access or decision power, and applies these principles consistently.
CO60
The community operates based on consensus of its members (see CS10) who have decision power. Dictators, benevolent or not, are not welcome in Apache projects.
CO70
The project strives to answer user questions in a timely manner.

Consensus Building

CS10
The project maintains a public list of its contributors who have decision power. The project's PMC (Project Management Committee) consists of those contributors.
CS20
Decisions require a consensus among PMC members 9 and are documented on the project's main communications channel. The PMC takes community opinions into account, but the PMC has the final word.
CS30
The project uses documented voting rules to build consensus when discussion is not sufficient. 10
CS40
In Apache projects, vetoes are only valid for code commits. The person exercising the veto must justify it with a technical explanation, as per the Apache voting rules defined in CS30.
CS50
All "important" discussions happen asynchronously in written form on the project's main communications channel. Offline, face-to-face or private discussions 11 that affect the project are also documented on that channel.

Independence

IN10
The project is independent from any corporate or organizational influence. 12
IN20
Contributors act as themselves, not as representatives of a corporation or organization.

Trademark and Branding

Notable items from the Trademark Policy, FAQ, Guide, and PMC Branding Responsibilities. The project’s PMC should comply with ASF’s branding and trademark policy in all places it controls.

TB10
The project uses "Apache Foo™" as the project and software product name consistently, with appropriate trademark attributions 13.
TB20
The project's primary homepage is at projectname.apache.org. When exceptions exist to use alternate domains for any purpose, any non-apache.org domain names are owned by the ASF.
TB30
The ASF has trademark rights, including any registrations, to the project name, logo, and any other major branding elements 14.
TB40
The project monitors for any major misuses of their project's brand by others, and reports 15 any potential misuses to Brand Management.

How To Use The Apache Project Maturity Model

Remember: This model is a 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, podlings preparing their graduation from the Apache Incubator have used this model, mostly for self-assessment.

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 document. Thanks to the many people who provided input! The links below are both inspirations for our model, and are some of the other ways that FOSS project participants have tried to quantify ways to measure open source projects.

Status / Document Version

v1.0, February 2015, defined by consensus by Apache Community Development project.

v1.1, October 2016 added RE50.

v1.2, February 2018, reworked the “how to use” section with more links to self-assessments.

v1.3, June 2021, improve readability and simplify the language where possible.

v1.4, December 2024, added the Trademark and Branding section (TB10-TB40).

See the svn revision history (for older versions) and GitHub history (since March 2020) of this document for more details and other minor changes.

Footnotes

  1. "For distribution to the public at no charge" is straight from the from the ASF Bylaws at https://apache.org/foundation/bylaws.html.

    (1)

  2. See also LC40.

    (2)

  3. 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.

    (3)

  4. https://apache.org/legal/resolved.html has information about acceptable licenses for third-party dependencies.

    (4)

  5. 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.

    (5)

  6. See https://www.apache.org/legal/release-policy.html for more info on Apache releases.

    (6)

  7. The required level of security depends on the software's intended uses, of course. Projects should clearly document security expectations.

    (7)

  8. Apache projects can just point to https://www.apache.org/security/ or use their own security contacts page, which should also point to that.

    (8)

  9. In Apache projects, "consensus" means widespread agreement among people who have decision power. It does not necessarily mean "unanimity".

    (9)

  10. For Apache projects, https://www.apache.org/foundation/voting.html defines the voting rules.

    (10)

  11. Each Apache project has a private mailing list that its 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 and committer candidates.

    (11)

  12. 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.

    (12)

  13. See https://apache.org/foundation/marks/pmcs#attributions for more information on trademark attributions.

    (13)

  14. For example, any transfers of existing trademark registrations during Incubation must completed before graduation.

    (14)

  15. See also https://apache.org/foundation/marks/reporting.html#pmcs for more information on reporting misuses.

    TB40 is a balancing act: we hope that PMCs are spending some time responding to any obvious or blatant misuses of their brand. But PMCs sometimes can’t handle all the details of actually stopping a potential infringement; what we really need is for PMCs to actively report them, and then promptly respond if Brand Managment (or other officers) ask for information when addressing a misuse.

    (15)