Apertus: Switzerland's First Fully Open Large Language Model

(EPFL, September 03, 2025)

Apertus has just been released to the public and emerges as Switzerland's first comprehensive, open, multilingual language model, spotlighting previously underrepresented languages such as Swiss German and Romansh. This achievement was made by Prof. Dr. Martin Jaggi, Dr. Imanol Schlag, and their team from ETH Zurich, EPFL, and the Swiss National Supercomputing Centre (CSCS). The team invested over 10 million GPU hours on the "Alps" supercomputer and secured funding from the ETH Board to train Apertus on 15 trillion tokens from over 1,000 languages, emphasizing non-English content. This extensive training ensures that Apertus excels in multilingual support, and could become a crucial tool for innovation across the economy, research, society, and industry. As a rare open large language model, Apertus stands out for its commitment to multilingualism, transparency, and ethical standards, offering a new model for inclusive and sovereign AI technology development.