Google Summer of Code 2026

Introduction

Google Summer of Code is a program that allows students to contribute to the development of open-source projects, mentored by participating organizations.

Particle physics is an exciting field where large collaborations of scientists collect and analyze petabytes of data from high-energy physics experiments, such as those at the Large Hadron Collider, hosted at the CERN laboratory in Geneva, Switzerland. Some of the questions that we collectively ask are:

What are the fundamental blocks that make up our Universe?
What is the nature of dark matter and dark energy?
What is the nature of the asymmetry between matter and antimatter?
What was early Universe like?

To answer these questions, particle physicists build software to simulate and analyze what happens in particle physics detectors.

The CERN software for experiments (CERN EP-SFT) group has participated in the GSoC since 2011. Since 2017 the program has expanded to involve the high-energy physics community under the umbrella of the HEP Software Foundation.

Information from last year’s GSoC can be found here.

GSoC 2026

In 2026 HSF is participating in the program as a GSoC umbrella organization, under the name CERN-HSF. The HSF project ideas are listed below. Please have a look at the general program rules and the timeline provided by Google.

The selection process in our organization will be split into two phases. All candidates will have to pass pre-selection evaluation tests prepared by mentors, demonstrating the skills needed for the respective projects. The successful candidates will have a detailed exchange with mentors on a given project idea, and their proposals are then evaluated for the final student selection. The detailed timeline of these phases is shown below.

For Students

If you are interested in the HSF projects, please start by having a look at our guidelines for students and frequently asked questions.

New projects for HSF GSoC in 2026 will be published by February 3rd. Meanwhile you can take a look at last year’s HSF GSoC projects since many of those may also propose subjects this year. The student application period will begin on Mar 16, but discussions about student project ideas with mentors will take place starting on February 19, when the list of accepted Organizations is announced. You are encouraged to monitor this website in order to get acquainted with our projects and be prepared for contacting their mentors. Due to the high number of applicants for CERN-HSF projects, the application period procedure become more formal this year, so please try to follow our guidance.

Please avoid having the first contact with the mentors of HSF projects before February 19 or after March 16! You are encouraged to take the time to read our project proposals, focusing on only one or two projects that attract your interest. Once you have identified those, you should e-mail the respective mentors, attaching your CV and describing the motivation for your choice. The mentors will first propose an evaluation test, waiting for your solution. Note that the test you are given is private, your solution should be personal and the response time is part of the evaluation. Mentors will let you know the test results, and if you passed they will start discussing and helping you develop a project idea. The student application period is March 16 - March 31, when you will have to write and review your proposal with help from your mentors.

For further information, feel free to contact the HSF GSoC admins or join our open chat channel below. Note that the channel is intended for exchanging with fellow contributors, the other candidates and some of the CERN-HSF students from previous year, and we do not maintain a mailing list for candidates. Please avoid posting extended information about yourself in the chat channel and reserve this for the direct exchange with the mentors.

hsf-gsoc-admin@googlegroups.com

Past Projects

Project from previous years are showcased in blog posts written by students. If you are a CERN-HSF student, please read these instructions on how to add your project. Student blogs are mandatory for receiving a positive evaluation in CERN-HSF!

See here the student blog posts from previous years:

For Projects and Mentors

Instructions for participating projects and mentors can be found here. The main differences compared to last year are that proposals can now be 90-hour, 175-hour or 350-hour project length, and the target objectives must be well-defined deliverables.

We have a mentor-only Google group where we handle all announcements related to GSoC for our HSF Umbrella Organization. Please write us a mail to hsf-gsoc-admin@googlegroups.com if you want to add your preferred email to this list. Note that all participating mentors in 2026 HSF GSoC will have to be added to this group. Please let us know if for some reason your want your mail removed from this list.

For new HEP-related groups wishing to join HSF GSoC umbrella rather than being independent organizations: there is no formal procedure, you will just need to add a description and logo for your organization. Note that your project needs to have some connection with high-energy physics to join us. We need one contact person for each new group, so please write us an e-mail.

Timeline

Jan 07	Announcement of GSoC 2026 program in HSF
Jan 07	Call for 2026 HSF GSoC projects and mentors
Jan 07 - Feb 01	Mentors add project proposals available on the HSF GSoC website
Feb 01	Deadline for CERN-HSF proposals
Feb 19	Accepted Organizations announced by Google
Feb 19 - March 16	Phase 1 selection Candidates have a first contact with project mentors.
March 16	Mentors announce to students the result of phase 1 selection
Mar 16 - March 24	Candidates discuss with mentors their project idea, timeline and objectives.
March 24 - March 31	Mentors help candidates improving their proposals, proposals are submitted
March 31	Student application deadline
March 31 - Apr 21	Phase 2 selection Mentors evaluate and rank student proposals.
April 21	Rankings due for mentors, sent to HSF Org Admins
April 21 - April 29	Admins propose a range of slots to be asked, amended by the HSF committee.
April 29	Student slot requests due for Org Admins
April 30	Accepted student projects announced

Projects in 2026

Will be filled by Feb 1st.

Participating Organizations in 2026

Summary

Full list of Proposal Ideas

Full list of Mentors

Contacts

HSF GSoC mentor discussion e-group

HSF GSoC administrators: Wouter Deconinck, Maciej Szymanski, Valentin Volkl, Aaron Jomy