# CZI Essential Open Source Software for Science (Cycle 6)

**Funder:** Chan Zuckerberg Initiative / Wellcome / Kavli
**Budget:** 2-year grants for open source software maintenance and development
**Deadline:** 15 April 2026 (Check CZI portal for exact deadline. Co-funded with Wellcome and Kavli Foundation. Supports critical open-source biomedical research software.)
**Duration:** 2 years
**Consortium:** No
**Application:** full-proposal
**TRL:** 3-7
**Frequency:** annual
**Next round:** 2027-03
**Official call:** https://chanzuckerberg.com/rfa/essential-open-source-software-for-science/
**Last verified:** 23 March 2026

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Source: [The Great Grantsby](https://grantsby.eu/grants/czi-eoss-cycle6-2026) — EU grant monitoring for academic researchers. Always verify details on the funder's website before applying.