NumFOCUS Project Support


NumFOCUS aims to ensure that funding and resources are available to sustain projects in the scientific data stack over the long haul. One of the ways we accomplish this vision is through programs that provide support for open source scientific computing projects: our fiscal sponsorship program and our affiliation program.

How does NumFOCUS support its projects?

NumFOCUS provides support for projects in three primary areas:

      • Community

      • Promotion

      • Funding



Project leaders benefit from participation in the NumFOCUS network, which includes leaders from a variety of scientifically oriented open source computing communities. NumFOCUS leverages our broad, international network to help build connections that support our projects. In addition to making strategic introductions, NumFOCUS creates opportunities for project leaders to connect with one another as a group, both in person and through digital forums.



NumFOCUS projects benefit from elevated visibility as a result of their association with the organization. We work to highlight all of our projects through various communications and marketing activities. We also find opportunities to showcase our projects with potential and current corporate sponsors.


All NumFOCUS-supported projects are eligible for funding through two of our programs:

Small Development Grants
NumFOCUS awards small development grants to help our projects improve usability, grow their communities, and speed up the time to major releases. Eligibility is limited to our fiscally sponsored and affiliated projects, and calls for proposals are run 3 times per year. Funds for the small development grants program are made possible by the generosity of our individual donors and corporate sponsors.

Google Summer of Code
NumFOCUS has participated as an umbrella organization for Google Summer of Code since 2015. Our fiscally sponsored and affiliated projects are eligible to participate in GSoC under NumFOCUS. We manage the administration of the program, which means that participating projects can focus on the mentoring relationship with their students.

There are two options for projects wishing to join NumFOCUS: fiscal sponsorship or affiliation.

How does Fiscal Sponsorship with NumFOCUS help projects?

Fiscal sponsorship helps projects attract and manage funding. Donations to NumFOCUS fiscally sponsored projects are tax-deductible.


Trademark Registration & Ownership
Contracts & Agreements


Accounts Payable & Receivable
Grant Administration
Contractor Agreements
Taxes & Reporting


Technical Infrastructure
Conference & Event Planning
Consulting on a variety of administrative requests

Two Types of Fiscal Sponsorship


Comprehensive Model

Fiscally sponsored projects under the Comprehensive Model formally become part of NumFOCUS — in other words, NumFOCUS maintains all legal and fiduciary responsibility for the project. Any work product of the Fiscally Sponsored Project is available to the public or to the charitable sector, and NumFOCUS assures funders that the purposes and any restrictions of all grants and/or contributions will be met. The Comprehensive Model of fiscal sponsorship helps protect individual contributors from legal liability and ensures project assets are owned by the project and not individual contributors.


Grantor-Grantee Model

The Grantor-Grantee Model is a “lightweight” option for fiscal sponsorship, for when a project is in need of an entity to receive and manage grant funding. In this model, the project remains a separate entity responsible for managing its own tax and liability issues. NumFOCUS ensures that the project will use the grant funds received to accomplish the ends described in the grant proposal, in alignment with our purpose as a 501(c)(3) public charity in the United States.

What are the requirements for a project to join NumFOCUS?

Be scientifically oriented.

NumFOCUS projects contribute to the advancement of scientific research. This means that the project either enables some new research challenges to be addressed or makes addressing research challenges significantly better (i.e. – faster, easier, simpler). This often means that the project has dependencies on or integrations with existing NumFOCUS projects.

While NumFOCUS projects typically take the form of an open community maintaining a software package, other types of non-software projects may still qualify. For example, projects with educational goals particular to scientific computing can be a good fit. See, for example, QuantEcon.

NumFOCUS supports projects that are part of a wider community; in the case of software projects, this would mean being interoperable with other projects in the same ecosystem. We support projects in various languages, including Python, Julia, R, C++, and JavaScript. Because NumFOCUS occupies itself with scientific tools, general-purpose projects (IDEs, utilities, programming languages, build systems, etc.) are typically not a good fit.



  • Project implements laws of general relativity in the form of an open source package for physicists
  • Project provides peer review of open source software packages for biology


  • Project is a software package for identifying open source dependencies and showing whether they are actively maintained
  • Project provides a platform for circulating petitions among academic scientists

Be open.

By “open,” we mean that the project is published under a standard open source license, and that it seeks engagement with the public as an intrinsic part of its development. Open projects typically have:

  • Publicly hosted code
  • A website or readme to orient new potential contributors to project development
  • Discussion forum(s) open to public participation (mailing list, Discourse, Slack team, etc.)
  • An OSI approved license
  • More than one contributor, as it’s highly unlikely a project will be accepted without a community of active contributors

The above is not meant to be a checklist for openness, but gives a sense of the characteristics typically associated with an active, open community.

We consider distributed decision making a key attribute of any open project and therefore require project leaders not to be concentrated in a single institution.


Additional Requirements for Fiscal Sponsorship:

  • A transparent, publicly visible governance model
  • A roadmap outlining high priority work areas

NumFOCUS requires fiscally sponsored projects to have an explicit governance structure listed publicly on the project website or documentation. It is important to have clarity around who has decision making powers for fiscally sponsored projects in order for NumFOCUS to effectively meet our obligations to funders, partners, and the government. For projects without formal governance in place yet, NumFOCUS is happy to suggest resources to help meet this requirement.

A project roadmap is an important document for fiscally sponsored projects because it shows that the project is mature enough to have a longer-term vision. This is also a crucial item for attracting significant funding to a project.



  • Best practices for submitting contributions are published on the project’s GitHub repo. Their website has a dedicated page to welcoming and directing new contributors to get involved.
  • Project has 4 currently active contributors and a number of other contributors who have done significant work for the project at some point in the past. Most contributors are in academia, but they are scattered across several institutions.


  • Project repos (of which there are many) have different licenses, and some are unlicensed.
  • The only text in the project documentation that relates to contributing states: “If you find any bugs, please email us.” The developer and contributor guide subsections of the manual are empty.

Be kind.

NumFOCUS wants to foster a constellation of healthy, productive communities. We believe that this can only be achieved if each project actively works towards making their community friendly, inclusive, and respectful of each participant. Examples include welcoming newcomers and friendly responses on public forums.

To NumFOCUS, an important part of “being kind” is stating openly the values and standards for the project community — and upholding them. To that end, NumFOCUS projects are required to have a Code of Conduct (CoC): a user-facing, public statement on inclusivity and project culture.

The CoC should include an explanation of what types of behavior are prohibited (and, ideally, what behavior is encouraged), as well as a procedure for reporting CoC complaints, an explanation of who is responsible for resolving CoC complaints (i.e. – a committee, names of project leaders, or similar), and the process by which CoC complaints will be addressed.



  • Project uses the Contributor Covenant Code of Conduct and has a designated point of contact or subcommittee to handle CoC violations or concerns.
  • Responses on issues seem to be friendly, tolerant, and encouraging, if at times sporadic or slow.


  • There is nothing on the project website to indicate that the project is not inclusive, but there are also no “positive” signals.
  • The project has nominally adopted the Contributor Covenant CoC but exhibits unwelcoming behavior to new contributors. No points of contact are listed for making CoC reports.

Apply to Join NumFOCUS

To apply for NumFOCUS Fiscal Sponsorship or Affiliation of your project, click “apply now.” Be sure to note the quarterly deadlines to apply, listed below.

Application Dates*

*June 15, 2023 Update: We’re capping the number of projects we accept for the remainder of the year to allow our team to focus on ensuring NumFOCUS has the infrastructure and resources to efficiently and effectively meet the needs of our projects and successfully scale the organization. Preference may be given to projects who are meeting deadlines or have pending grants or funding opportunities.

Project Applications are accepted on a quarterly basis.

Application rounds will close on the following yearly dates:

January 15 (Round 1)
April 15 (Round 2)
July 15  (Round 3)
October 15 (Round 4)

Notifications will be sent on or before:

February 28 (Round 1)
May 31 (Round 2)
August 31 (Round 3)
November 30 (Round 4)