Localization Lab

Free and Open Source Software Sustainability Fund

The Free and Open Source Software (FOSS) Sustainability Fund is Open Technology Fund’s newest mechanism to support the long-term maintenance of established FOSS projects and the communities that sustain them.

Not currently accepting applications

About the FOSS Sustainability Fund

For the past decade, Open Technology Fund has helped people around the world exercise their fundamental human rights online by supporting innovative open-source technologies. Today, many of these technologies are the foundation of the free and open internet. Despite the critical role that open source technologies play in protecting human rights and free expression, they are perpetually under-funded and under-supported. As a result, these critical technologies are in danger of becoming defective or even developing security risks if they aren’t properly maintained.

In response to this challenge, the FOSS Sustainability Fund helps to ensure that free and open source software projects and the communities that sustain them have the resources and support needed for long-term maintenance, security, and community well-being. Ensuring a diverse, vibrant, and sustainable FOSS ecosystem is critical to OTF’s commitment to support the development and maintenance of anti-censorship technologies, and ensures that all users have better access to privacy and security tools.

OTF launched the FOSS Sustainability Fund in 2023 with support from Schmidt Futures’ Plaintext Group, Omidyar Network, Okta, and GitHub. We are proud to support this fund in collaboration with other organizations that value open source technologies and invest in the security and sustainability of these tools. In addition to expanding support for these critical technologies, these contributions also help to match OTF’s Congressional funding with non-federal resources and deliver on OTF’s mandate to maximize cooperation between public and private sectors.

Application Process and Award Information

Applications to the FOSS Sustainability Fund go through a two-stage application process and are accepted during open solicitation.

Funding awards are performance-based contracts signed directly with the applicant or applicants. Funding is dispersed upon completion of stated objectives, activities, and deliverables as outlined in the contract. All payments are made in U.S. dollars and will comply with local laws, regulations, and ethics rules.

Successful applicants are paired with an OTF program manager who will oversee all project monitoring and evaluation for the duration of the contract. Monitoring and evaluation assessments are based on predetermined and agreed-upon metrics, deliverables, and goals as laid out by the applicant in the project proposal.

Subject to availability of funds, OTF expects to support up to four projects ranging from $150,000 to $400,000 for approximately 24 months.


The Fund is available to all internet freedom FOSS tools, apps, open standards, protocols and libraries, that have come into shape from inception to development, and are seeking to work on the sustainability of the project beyond initial release. Applicants must meet the following qualifying conditions to be considered eligible:

  1. Release: Software has been released for at least 3 years.
  2. Updates: The project pushes updates at least 4 times a year. 
  3. Development: Active coding towards the software has occurred in the last 2 years.
  4. Userbase: The project has a substantial base of active users, if it is an app or other user-facing tool.
  5. Keystone technology: OTF aims to support projects with many dependencies, to maximize long-term impact in the broader FOSS ecosystem.

Individuals or organizations* (for-profit or nonprofit) of all ages irrespective of nationality, creed, or sex are encouraged to apply.

OTF is not able to support applicants within countries that the United States has trade restrictions or export sanctions as determined by the U.S. Office of Foreign Assets Control (OFAC).

Areas of Focus

OTF supports the long-term sustainability of FOSS from a holistic perspective, considering both the technical and human elements necessary for project health and longevity. While a FOSS Sustainability Fund project may fall under a single area of focus below, many successful projects will incorporate multiple areas in their application. Each applicant will have different needs based on their level of maturity, size, adoption, and other factors (see the Eligibility section above for the baseline requirements). But, each project must consider balancing operational and community needs versus technical needs when considering their priorities for their long-term sustainability. Rather than providing ongoing core funding, this Fund invests in a project’s current and future sustainability.

For projects looking to create new technologies or add new features to existing technologies, please consider applying for the Internet Freedom Fund instead.

The following areas of long-term sustainability are illustrative and not meant to be exhaustive, and some activities naturally overlap across different areas. We welcome applications proposing new sustainability areas and activities of sustainability so long as the proposal makes a strong justification for them.


Maintenance activities are the technical activities essential to ensure long-term sustainability. These can be corrective (patching bugs or remediating vulnerabilities), adaptive (modifying to a changing environment), or enhancing (rebuilding or upgrading based on user feedback or improving efficiency). Examples include:

  • Codebase migration
  • Code refactoring
  • Infrastructure upgrades
  • Architecture rebuilds
  • Security upgrades and enhancements
  • Responding to new threat models
  • Clearing bug backlog
  • Usability and accessibility improvements*


Operations activities run the gamut of things needed to ensure a project remains operationally active. These activities include both the technical and social elements, and center around improving contributor productivity, open source viability, and project stability. Examples include:

  • Refined contributor workflows
  • Project management
  • Accounting 
  • Code optimization and styling
  • Improve licensing
  • Aligning with open source principles
  • Testing infrastructure
  • Updating documentation
  • Creating and following a sustainable business plan
  • Software evaluations
  • Long-term strategic planning 


People are at the heart of any successful FOSS project. These community activities center around the health and wellbeing of the contributor base, and the engagement of and responsiveness to users. Examples include:

  • Ecosystem wellbeing 
  • Community management 
  • Governance
  • Organizational health
  • Improving diversity
  • Growing contributor base
  • Improve user feedback loops*
  • Contributor and user communications
  • Language localization*
  • Visuals and website*

* Applicants should consider OTF Lab support for these services, which can be independent of or in coordination with a FOSS Sustainability Fund project. OTF Labs offer support provided by expert community partners. See below for more information. 

How to Apply

Applying for the FOSS Sustainability Fund is a two-stage application process:

Stage 1: Once the solicitation opens, submit a Concept Note through OTF’s online application system in which you tell us about your project idea through a short form.

Stage 2: Applicants whose Concept Notes are deemed to be highly competitive will be invited to submit a Proposal in which they will expand upon their project idea.

The FOSS Sustainability Fund Advisory Council, comprising subject-matter experts who understand the relevant fields and issues related to the sustainability of the FOSS ecosystem, will conduct a final review of competitive Proposals.

Please review our Applicant Guidebook for additional information about our application process, especially the Concept Note Guide and Review Process sections.

Application Review Process

How OTF evaluates FOSS Sustainability Fund applications:

Did the applicant establish how the proposed activities will impact the FOSS project’s long-term sustainability, not just short-term maintenance? 

Will the FOSS project survive beyond the life of OTF’s support?

Does the applicant consider both technical and social aspects of sustainability?

Does this project have dependencies that impact other projects in the FOSS ecosystem? 

Is it cost effective?


Please direct any questions to [email protected].



OTF Labs Support

OTF Labs provide critical services to internet freedom projects that are not covered by our other funding mechanisms. From security and usability audits to accessibility and communications strategy, the Labs ensure internet freedom projects are as effective, secure, and accessible as possible.

Red Team Lab – This lab provides security audits for internet freedom and FOSS projects. Audits are required for all OTF-funded technology projects, including FOSS Sustainability Projects, but applicants can apply for audits without separate funding, as well. Read more about this lab and how to apply here.

Secure Usability and Accessibility Lab: This lab provides in-kind secure usability and accessibility services to OTF-funded projects and other FOSS projects who apply. Major components of FOSS projects’ long-term sustainability include responding to user feedback and ensuring tools are usable and accessible for users. FOSS Sustainability Fund-supported projects are offered at least 3 initial coaching sessions. Read more about this lab’s other services and how to apply here.

Learning Lab – This in-kind service helps OTF-supported projects with their communications needs and contributes to knowledge sharing. Learning lab vendors can support FOSS Sustainability Fund projects with research, writing, editing, graphic design, and communications strategy. Read more about this lab and how to apply here.

Localization Lab: This Lab works with global partners to help translate technologies into as many languages as possible to increase adoption around the world, support long-term sustainability. Read more about this lab and how to apply here.

Other Provisions:

OTF reserves the right to accept or reject any or all bids, to take exceptions to the RFP specifications, and to waive any requirements stated herein.

OTF reserves the right to make an award based solely on the proposals or to negotiate with one or more vendors.  Issuance of this RFP, preparation, submission, and evaluation of bidder responses does not commit OTF to award a contract to any vendor.  The award of a contract does not guarantee the award of work orders under that contract, which will vary based on need and availability. OTF reserves the right to cancel or modify this solicitation at any time for any reason within its sole discretion without liability.

OTF, in its sole discretion,  will make the final determination as to the acceptability of all work products due hereunder.

The vendor shall not issue, or permit to be issued, during the period covered by this contract or at any time thereafter, publicity in any form respecting the work hereunder or the fact of its participation herein, unless such publicity is first approved in writing by OTF.

In the event any portion of the cost of the services provided hereunder includes travel cost reimbursement, the vendor shall obtain advance approval of OTF and all travel expenditures must conform to the Standard Government Travel Regulations.

The vendor hereby agrees that all Work Product produced under the contract will be the sole  property of OTF and the fees to be paid to the Vendor are full, fair and adequate compensation for Vendor’s conveyance to OTF of copyrights in all Work Product.

The awarded contract will be based on OTF’s standard contract terms, including a termination for convenience provision, and will also include the relevant U.S. Government provisions, which are attached here as Appendix A.