Welcome to Hack Apertus, an open-source hackathon movement built around Apertus, the fully open large language model. Hack Apertus is a three-stage hackathon series with an Online Hackathon and six On-site Hackathons in Swiss cities, running from October 2026 until May 2027. Interdisciplinary teams build on Apertus to create reusable blueprints deployable air-gapped, on-premise, or on sovereign cloud infrastructure. You can join any hack, or all of them. Thanks for joining and contributing your time and expertise. π
Apertus is Switzerland's fully open LLM, developed by EPFL, ETH Zurich and CSCS within the Swiss AI Initiative (SNAI). It is open weights + open data + full training recipes, trained on 1,800+ languages (incl. Swiss German and Romansh), and developed with the EU AI Act in mind. First released 2 September 2025 under Apache 2.0; the 1.5 versions (8B/70B) followed on 24 July 2026.
Hack Apertus builds on the v1.5 family: continued pretraining of Apertus 1.0 that adds multimodal input, tool use, and up to 262k-token context.
| Stage | Dates | Details |
|---|---|---|
| 01. Online Hackathon | Oct 1β16, 2026 | Open to everyone worldwide. Use case prototypes, model adoption, and academia challenges |
| 02. On-site Hackathons | Oct 2026 β May 2027 | 2-day local hacks in Bern, Zurich, Basel, Biel/Bienne, Lausanne & St.Gallen |
| 03. Grand Finals | May 14, 2027 | Closing showcase and pitch competition of all Hack winners for the main Β«Hack ApertusΒ» Award in St.Gallen |
| Model |
|---|
swiss-ai/Apertus-v1.5-8B |
swiss-ai/Apertus-v1.5-70B |
| Apertus 1.5 multimodal |
swiss-ai/Apertus-8B-Instruct-2509 |
v1.5 weights are gated. Log in on Hugging Face and accept the conditions to download. Deployment is supported in Transformers and vLLM.
Apertus & the Swiss AI Initiative
Run & access Apertus
π hackapertus.ch Β· βοΈ hello@hackapertus.ch Β· πΌ LinkedIn
Initiated by aiLights, Artifact and Swiss Engineering.