Apertus (LLM)

Apertus is a public large language model, developed by the Swiss AI Initiative (a collaboration between EPFL, ETH Zurich, and the Swiss National Supercomputing Centre).^[1] It was released on September 2, 2025,^[2] under the free and open-source Apache 2.0 license.^[3]

Designed initially for business and research use cases around the world,^[4] Apertus was trained on over 1800 languages, and comes in 8 billion or 70 billion parameter versions and is available on Hugging Face for download.^[5][6] The model was developed aiming to adhere to European copyright law, and is one of the first examples of AI as a public good in the vein of AI Sovereignty.^[6][7][8] It is also the first large model to comply with the European Union's Artificial Intelligence Act.^[9][7] At its launch, the model creators emphasized multilinguality, transparency, and auditability as priorities in contrast to commercial frontier model.^[10] While international reception was largely positive^[11], the first iteration was significantly behind the capabilities of frontier models^[4] and needs adaptation for many use cases with chatbots being a secondary but not a primary use case.^[5]

As of late 2025, it was considered the largest and most capable fully open model.^[4] The capability of future models will depend in part on how much more funding can be secured.^[5]