# Essential Open Source Software for Science

**Funder:** CZI
**Budget:** $100,000–$400,000 USD
**Duration:** 2 years
**Consortium:** No
**Application:** 2-stage: Letter of Intent → Full Application
**Frequency:** Recurring
**Official call:** https://chanzuckerberg.com/rfa/essential-open-source-software-for-science/
**Last verified:** 23 June 2026

## Summary

Essential Open Source Software for Science funds projects that develop, maintain, or enhance critical open-source tools used by the scientific community, with awards of $100,000-$400,000 USD over two years. The call is open to developers, researchers, and teams building or stewarding software that serves broad scientific needs. This is a recurring programme run jointly by the Chan Zuckerberg Initiative, Wellcome Trust, and The Kavli Foundation.

## Who should apply

- Software developers and research software engineers maintaining tools used across disciplines
- Researchers leading collaborative teams building widely-adopted open-source solutions
- Projects addressing bottlenecks in scientific computation, data analysis, or visualization
- Applicants with demonstrated user base or community adoption of their software

## Key dates

- This call closed on 17 October 2023; future deadlines will be announced on the funder websites
- Two-stage process: Letter of Intent followed by Full Application
- Two-year project duration

## Tips for applicants

- Quantify the user base and scientific impact of your software, funders want evidence of real-world adoption, not potential.
- Address sustainability explicitly: explain how the software will be maintained after the funding period ends.
- Letters of intent that propose incremental feature work score lower than proposals that tackle fundamental maintenance, interoperability, or accessibility challenges.

## Frequently asked questions

### How much does the Essential Open Source Software for Science grant pay?

Awards range from $100,000 to $400,000 USD per project over two years.

### Who can apply for Essential Open Source Software for Science funding?

Software developers, research engineers, and research teams building or maintaining open-source tools used by the scientific community are eligible.

### Is Essential Open Source Software for Science a recurring call?

Yes, the programme is recurring and run jointly by the Chan Zuckerberg Initiative, Wellcome Trust, and The Kavli Foundation; check their websites for the next deadline.

### What types of software projects are funded?

Projects that develop, maintain, or enhance critical open-source tools serving broad scientific needs, such as data analysis, visualization, computation, or infrastructure, are prioritised.

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Source: [The Great Grantsby](https://grantsby.eu/grants/chan-zuckerberg-initiative-wellcome-trust-the-kavl-essential-open-source-software-for-science-2026) — EU grant monitoring for academic researchers. Always verify details on the funder's website before applying.

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