Google Summer of Code (GSoC)
253 organisations took part between 2024 and 2026. 200 have repositories measured so far, last updated 11 Oct 2026.
The ranking rule. Share of pull requests from outside the core team that got a reply from a person within 7 days, across all of the organisation's measured repositories. Ties go to the higher outside merge rate. An organisation needs at least 20 outside pull requests to take a place; smaller ones follow, unranked.
Each year Google funds new contributors to spend about 12 weeks building something for an open source project.
You work with a mentor from the organisation you applied to. You do not need to be a student, only new to open source and 18 or older.
You write a proposal to one of the organisations below. That is why it matters which of them reply to newcomers.
Details and dates are on the official Google Summer of Code site.
Now is the best time to start: contribute small fixes to the organisation you want, so the mentors know your name before applications open.
Oct
You are here.
Organisations
213 organisations measured on GitHub
40 organisations cannot be measured on GitHub. They host their code elsewhere, or they are umbrella organisations whose projects change every year. They are listed so the ranking does not pretend they do not exist.
Mid January
Many publish their idea lists now.
Late February
Pick two or three and read their ideas.
Applications
Mid March
Send mentors a draft early for feedback.
End of March
About two weeks after opening.
End of April
Meet your mentor before coding starts.
Coding
Late May
About 12 paid weeks, midterm in July.
Late August
Larger projects can run into November.
Google has not published the 2027 dates yet; these follow the 2026 programme, which has kept the same shape for years. Official timeline
Start with OpenRefine/OpenRefine
Python-based CMS, with React front-end.
GSoC 2024, 2025 · 12 repositories measured
pythonjavascriptreact
Start with plone/volto
Nonprofit building a global digital commons.
GSoC 2024 · 12 repositories measured
pythonjavascriptphpcsswordpress
Start with creativecommons/cc-legal-tools-app
We code immersive and interactive apps with GEarth
GSoC 2024, 2025, 2026 · 7 repositories measured
linuxandroidnodejsfluttergoogle earth
Start with LiquidGalaxyLAB/Data
Writing robust tools for the Wayland protocol
GSoC 2024, 2025 · 12 repositories measured
cc++rustwaylandzig
Start with waycrate/xdg-desktop-portal-luminous
Advancing Computer Vision & Spatial AI, Openly
GSoC 2025, 2026 · 1 repository measured
cudarustdeep learningdata sciencespatial ai
Start with kornia/kornia-rs
XSF develops an open-standard messaging protocol
GSoC 2024 · 1 repository measured
javascriptjava
Start with xsf/xeps
Prevent programming errors via simple verification
GSoC 2025 · 2 repositories measured
javacompilersverificationformal methodstype systems
Start with typetools/checker-framework
Promote Open Standards and Open Source
GSoC 2024, 2025, 2026 · 7 repositories measured
javascriptc/c++nodejspython 3machine learning (ml)
Start with eellak/spdx-storage
JPF is a Java VM used to verify and debug software
GSoC 2024, 2025, 2026 · 1 repository measured
androidjavadistributed systemsjvm
Start with javapathfinder/jpf-core
Dates for the next round are published by Google on the official timeline. Contributable is independent and not affiliated with Google.