What it is
Apertus-8B-Instruct-2509 is a language model for chat, drafting and question answering, published by the Swiss AI Initiative (EPFL and ETH Zurich) on Hugging Face on 13 August 2025. It has about 8.1 billion parameters and a configured context window of 65,536 tokens.
Its card lists the licence as Apache 2.0. In short, the licence allows commercial use, modification and redistribution, with attribution and a copy of the licence, and includes a patent grant.
Hugging Face counted about 452,881 downloads of it in the 30 days before we checked (7 Oct 2026), and 495 people have liked it there.
It is built on swiss-ai/Apertus-8B-2509, according to its card.