Apertus

Apertus is Switzerland's first large-scale public language model, released on September 2, 2025 by the Swiss AI Initiative — a collaboration between EPFL, ETH Zurich, and the Swiss National Supercomputing Centre (CSCS). It ships in 8B and 70B dense variants under the Apache 2.0 license, and its openness goes unusually far: architecture, weights, training code, intermediate checkpoints, and the training-data pipeline are all public.

Trained on more than 15 trillion tokens spanning 1,500+ languages (40% non-English, including Romansh and Swiss German) on the Alps supercomputer's 10,000+ NVIDIA GH200 chips, it was built for GDPR and EU AI Act compliance from the start. Reception noted genuine transparency leadership alongside a candid caveat: the first iteration trailed frontier models on raw capability, and chat is a secondary use case — Apertus is infrastructure for sovereign, auditable AI rather than a ChatGPT rival.