Fiscal Sponsorship

Most open source projects, even the wildly successful ones, struggle to develop the operational framework necessary for long-term sustainability. NumFOCUS provides a critical service to our projects as an umbrella organization and fiscal sponsor. Our deep expertise in nonprofit administration enables project contributors to focus on what they care about most—development and maintenance of the project itself.

What is a Fiscally Sponsored Project?

Fiscally Sponsored Projects are open source projects that enter into a specific contractual and legal relationship with NumFOCUS. The agreement confers the project with all the benefits of NumFOCUS’s nonprofit status as a 501(c)(3) public charity in the United States, which enables collection of tax-deductible contributions and confers eligibility for grant funds restricted to qualified nonprofit organizations. NumFOCUS ensures that all funds directed to Fiscally Sponsored Projects will further our nonprofit mission and be used for tax-exempt purposes. In exchange, NumFOCUS takes a small percentage of any funds directed to the project to cover costs associated with handling all taxes, financials, and legal matters for the project.

Comprehensive Model

The Comprehensive Model of fiscal sponsorship means that the project becomes a program of NumFOCUS. NumFOCUS then 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. NumFOCUS assures funders that the purposes and any restrictions of all grants and/or contributions will be met.

Comprehensive Template

Grantor-Grantee Model

In addition to the Comprehensive Model described above, NumFOCUS also offers a Grantor-Grantee Model of fiscal sponsorship. In this model, the project remains a separate entity responsible for managing its own tax and liability issues. Instead, NumFOCUS simply assures itself that the project will use the grant funds received to accomplish the ends described in the grant proposal.

Grantor-Grantee template

How does Fiscal Sponsorship help the projects?

Fiscal Sponsorship helps projects attract funding. Corporate contributions to Fiscally Sponsored Projects are tax-deductible. Fiscal Sponsorship provides both financial administration and legal services for sponsored projects. The Comprehensive Model of fiscal sponsorship has other benefits, such as protecting individual contributors from legal liability and ensuring project assets are owned by the project and not individual contributors.


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

NumFOCUS Sponsored Projects

pandas logo
Julia logo
Bokeh logo
Econ-ARK logo
Cantera logo

pandas logo
Bokeh logo
Julia logo
Econ-ARK logo
Cantera logo

pandas logo
Julia logo
Bokeh logo
Econ-ARK logo
Cantera logo

NumFOCUS Fiscal Sponsorship Meets Critical Project Needs


Projects need funding to support paid maintainers (both full-time and part-time) and periodic development sprints.

  • NumFOCUS provides the legal, professional, and financial services that enable projects to attract and manage funding.


Maintainers of projects in the scientific data stack tend to move around quite a lot! As individuals move through different institutions, employers, countries, and stages of their career, the amount of time and resources they can spend on a project will shift. Projects need stable institutional support to weather these changes.

  • NumFOCUS provides a central hub that continues to link and support projects even when the people working on them change and move.


We believe scientific inquiry should proceed free of politics and agendas. Scientific progress is at risk if we leave critical projects dependent upon particular individuals, corporations, or research institutions for support.

  • NumFOCUS functions as a neutral, unbiased, and independent organization designed solely to support the community that develops and maintains the open source scientific data stack.

Logistical Support

Scientists and programmers want to do the work they are trained for, good at, and enjoy. They are often ill-equipped to tackle the logistical needs of sustaining a project, such as managing financials, handling legal issues, working with contractors, and identifying funders.

  • NumFOCUS handles most administrative, financial, and logistical responsibilities for projects, freeing scientists and programmers to concentrate on their work.

What are the requirements to become a Fiscally Sponsored Project of NumFOCUS?

A Fiscally Sponsored Project must further the NumFOCUS mission and:

  1. Release its code under an OSI approved open source license (exceptions must be approved by the NumFOCUS Board of Directors)
  2. Have a Code of Conduct, either adopted from our own or similar in spirit.
  3. Have a community that is active and of reasonable size
  4. Have multiple people willing to sign the Fiscal Sponsorship Agreement (5 signatories for a comprehensive FSA; 3 signatories for a grantor-grantee FSA). Those people must be active in the project; one person may be an external stakeholder instead of a project contributor.​
  5. Have a leadership body or team consisting of at least 3 people; these people should not be employed by the same entity or share a common affiliation beyond that of the project.

The project should have a focus on scientific computing or data science.

  • General-purpose projects (IDEs, utilities, programing languages, build systems, etc.) are typically not a good fit.

It is important that a project, if its main output is code, is either part of or integrates well with the wider open source scientific computing stack.

  • Python, Julia and R all communicate well with each other and with native code – this is one of the strengths of the data science ecosystem. A common barrier to integration is a dependency on a library or runtime that is not available to most users.

Projects with educational goals particular to scientific computing may also be a good fit. (See, for example, QuantEcon.)

The language(s) in which a project is written is not critical — currently, our sponsored projects already span a range of languages (Python, Julia, R, C, C++, Cython, JavaScript, and more).

The final decision on whether to accept an application for Fiscal Sponsorship is made by the NumFOCUS board on the basis of the criteria listed above.

​Learn more by reading the FSA FAQ linked here. General information on Fiscal Sponsorship is also available from the National Council of Non-Profits.

Apply for Fiscal Sponsorship

If your project is interested in applying for NumFOCUS Fiscal Sponsorship or would like additional information, please email us at to set up a call with our Executive Director.

Fiscal Sponsorship not the right fit?

We also have an Affiliated Projects program.


Science needs open-source software.

Osvaldo Martin, Supporting Member