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
A fresh approach to technical computing
GSoC 2024, 2025, 2026 · 1 repository measured
machine learningjuliadata sciencecompilersgarbage-collection
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 JuliaLang/julia
We develop genomics tools to benefit human health
GSoC 2024, 2026 · 12 repositories measured
pythonpostgresqljavareactrust
Start with ga4gh/vrs-python
LLVM Compiler Infrastructure
GSoC 2024, 2025, 2026 · 1 repository measured
llvmc++clangmlir
Start with llvm/llvm-project
Open source software for smart legal contracts
GSoC 2024, 2025, 2026 · 12 repositories measured
pythonjavascriptjsonreactartificial intelligence
Start with accordproject/apap
Using Computers to Fix Climate Change
GSoC 2024, 2025 · 12 repositories measured
pythonpytorch
Start with openclimatefix/quartz-api
Start with ceph/ceph-csi
The fastest growing Open Source Database
GSoC 2024, 2025, 2026 · 1 repository measured
pythonc/c++perldatabases
Start with MariaDB/server
Open source IP, tools & standards for ASIC/FPGA
GSoC 2024 · 12 repositories measured
fpgachiselrisc-vsystemverilogasic
Start with chipsalliance/Caliptra
The Hackable Network Management System
GSoC 2024, 2025, 2026 · 12 repositories measured
pythonjavascriptdjangoluaopenwrt
Start with openwisp/openwisp-radius
The powerful Python CMS for modern websites
GSoC 2024, 2025, 2026 · 12 repositories measured
pythonjavascriptdjango
Start with wagtail/wagtail
Dates for the next round are published by Google on the official timeline. Contributable is independent and not affiliated with Google.