What is European Summer of Code?
European Summer of Code (ESoC) funds stipends for contributors new to open source, and matches open source projects and applied AI projects throughout Europe. We are much indebted to the Google Summer of Code for inspiration.
- Work with experienced mentors
- Build your portfolio
- Receive stipends for your work
- Join a community of like-minded developers
- Connect with applied projects and sponsors
- Increase visibility for your project
- Receive support for your ecosystem
- Expand your contributor base
- Connect with relevant open source projects
- Find talented developers
- Accelerate your development
- Contribute to the open source community
Program Details
Learn how European Summer of Code works for applicants, projects, and sponsors.
Projects
2025 projects are released in three batches: March 27, April 10, and April 25. Projects have their own timelines and may come with their own terms of conditions.
Application Process
Applicants need to do two things to apply:
- 1
Register for ESoC
Complete the ESoC applicant registration form. - 2
Follow Project-Specific Steps
Follow any additional 'how to apply' steps from the project card of your preferred projects.
- 3
Meet Deadlines
Complete both steps before the project application deadline or batch deadline.
- 4
Wait for Results
You will receive a letter from ESoC on your application(s) no later than 6 weeks after the application deadline.
Recommendations
Ensure your submitted email address is correct, use the same name and email throughout the process, and submit early to avoid technical issues close to deadlines.
Onboarding Process
Private and public sector organizations wishing to host a project should submit a project sponsor form. Open source projects should directly contact our LinkedIn organization. Contact us on LinkedIn.
Funding Models
Choose between two funding models:
- 1
Option A: Donation for Stipend
You donate to a hub, and the hub contracts with the participant. The 'stipend' requires that a significant portion of the outputs are in the open domain.
- 2
Option B: Paid Internship
You can use your own contract template, in this case the hub will only act as matchmaker, and you will directly contract with applicants.
Project Card
Project cards should include: project title, logos, description, goals, organization info, technical details, application instructions, and deadlines.
Current Hubs
ESoC is organized in a decentral and distributed fashion, by hubs across Europe:
Hub Network
Current hubs include:
Expansion
We are actively looking to expand our network of hubs and affiliated open source projects. Get in touch on LinkedIn to discuss details.
Program Timeline
Key dates and milestones for the European Summer of Code 2025 program.
Early Bird Projects Released
First batch of projects released, including Applicant Guide and Sponsor Guide.
ProjectsAnnouncementEarly Bird Application Deadlines
Deadlines for early bird projects (varies by project).
DeadlineApplicationsSecond Batch of Projects Released
Second batch of projects published.
ProjectsAnnouncementBatch 1 Application Deadline
Deadline for completing both ESoC application form and project-specific steps for batch 1 projects.
DeadlineApplicationsThird Batch of Projects Released
Final batch of projects published.
ProjectsAnnouncementBatch 2 Application Deadline
Deadline for completing both ESoC application form and project-specific steps for batch 2 projects.
DeadlineApplicationsBatch 3 Application Deadline
Deadline for completing both ESoC application form and project-specific steps for batch 3 projects.
DeadlineApplicationsApplication Results
Applicants receive results no later than 6 weeks after the application deadline of their batch.
ResultsNotification
2025 Project List
Explore and apply for projects in ESoC 2025! Note project specific application deadlines.
Contribute to skore, the scikit-learn sidekick! Help improve data visualization in skore by implementing more displays, a Plotly display backend and providing access to underlying display data.
Contribute to pixi, the universal package manager! Help improve user experience, build user interfaces, and extend scope to more programming languages!
Contribute to rattler, fast mamba packager! Work on rattler-build to implement build process mechanisms, parallelize package installation, and improve the user experience.
Contribute to Gradient-Free-Optimizers & hyperactive! Help improve the Python toolboxes for optimization and data collection. Projects include implementing new optimizers, improving documentation, and more!
Build AI for design and equipment qualification of cleanrooms for biotech and pharmacological applications! Work with German engineering services provider ecoSPECS to fundamentally accelerate qualification processes in drug development, production, and monitoring worldwide.
Contribute to sktime! sktime offers a unified API for forecasting, classification, detection, and other learning tasks. Exciting projects are available in the areas of deep learning, foundation models, probabilistic forecasting, and more.
Affiliated Open Source Projects
Meet some of the open source projects affiliated with the European Summer of Code 2025.
