Overview
Hack Apertus is the online opening stage of an open-source hackathon series focused on evaluating, aligning, and building with Apertus, Switzerland’s fully open large language model. From October 1 to 16, 2026, participants will work remotely with the Apertus 1.5 8B and 70B models. Projects are intended to remain open and reusable. The event is open to participants around the world who are above the legal age of majority in their country of residence, subject to the listed country and territory exclusions.
Apertus was built by teams from EPFL, ETH Zurich, and CSCS, and the page says it was trained across 1,811 languages. The hackathon is aimed at people interested in open and trustworthy AI, including AI and machine learning engineers, software developers, data scientists, researchers, NLP practitioners, relevant students, and domain specialists in areas such as law, medicine, dialects, and the public sector.
Tracks and challenges
Participants can choose between two tracks. Apertus Readiness focuses on improving the model, with challenges in Red-Teaming Apertus and Swiss Voices. Apertus Adoption focuses on demonstrating what the model can do, through Academia Challenges or an Own Project. Detailed challenge descriptions and track-specific submission requirements are provided in the Getting Started Guide, scheduled for release on October 1 at 12:00 CEST.
For the Own Project track, the listed judging criteria include purposeful use of AI, technical rigor, value, cost and scalability, sovereign deployability, and implementation feasibility. Other tracks refer participants to their challenge descriptions for judging details.
Schedule and format
Participants are encouraged to join the event’s Discord, which serves as the main communications channel, and can use it to find teammates. Teams may have one to five members, and solo participation is allowed. Tracks and challenges are released October 1 at 12:00 CEST. During the event, participants can book mentor sessions, attend available online support sessions, and work remotely on their solutions. Final submissions are due October 16 at 12:00 CEST, with no extensions. An expert jury is expected to review submissions and select winners by October 23, 2026.
Judges and support
The listed judges are Isabel Steiner, President of aiLights and Migros Online; Dr. Wiebke Hutiri; Dr. Klaus L. Fuchs, Managing Director at Rockstar; Prof. Dr. Andreas Martin of FHNW; Oleg Lavrovsky, Technical Community Manager at SNAI; and Prof. Dr. Siegfried Handschuh of the University of St. Gallen. Mentors are also available to participants. The page identifies CSCS and Phoeniqs among the partners supporting work with the models.
Prizes and what follows
The page lists more than €10,680 in prizes, including cash awards and partner credits or other benefits across the challenges. Some first-place winners qualify to compete for the Main Hack Apertus Award at the Grand Finals in St. Gallen on May 14, 2027. This online stage is the beginning of a longer series that will include more than six on-site hackathons across Switzerland. Participants may join one or multiple stages; online and on-site events are separate phases.
