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
Homework Autograding and Course Management Tools
GSoC 2024, 2026 · 9 repositories measured
pythonpostgresqljavascriptc++php
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 Submitty/Submitty
We enable the reliable use of JSON data format.
GSoC 2024, 2025, 2026 · 6 repositories measured
pythonjavascripttypescript.netjson schema
Start with json-schema-org/JSON-Schema-Test-Suite
Modern and immersive programming language
GSoC 2025, 2026 · 1 repository measured
gitsmalltalkpharospecsunit
Start with pharo-project/pharo
Helps to adheres of Java coding standard
GSoC 2024, 2025, 2026 · 8 repositories measured
javaantlrartificial-intelligence
Start with checkstyle/checkstyle
State of the art fuzzing for better security
GSoC 2024, 2025 · 6 repositories measured
llvmrustfuzzingqemu
Start with AFLplusplus/AFLplusplus
Evolve the programmable data plane ecosystem!
GSoC 2024, 2025, 2026 · 12 repositories measured
llvmc++linux kernelmlirebpf
Start with p4lang/PI
State-of-the-art video conferencing
GSoC 2024, 2025, 2026 · 12 repositories measured
javascriptjavareactkotlinwebrtc
Start with jitsi/docker-jitsi-meet
Domain specific language for audio
GSoC 2024, 2025, 2026 · 1 repository measured
cjavascriptc++rusttypescript
Start with grame-cncm/faust
Rizin reverse engineering framework and toolset
GSoC 2024, 2025, 2026 · 12 repositories measured
cpythongoc++qt
Start with rizinorg/cutter
NumFOCUS promotes open source scientific software.
GSoC 2024, 2025, 2026 · 75 repositories measured
pythonc++rjulia
Start with holoviz/lumen
Dates for the next round are published by Google on the official timeline. Contributable is independent and not affiliated with Google.