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What makes Apertus different from other open models?

Apertus is fully open, offering complete access to training data, code, and alignment principles, not just open weights. This openness supports research, collaboration and informed use, creating a valuable tool for the global AI community. See Swiss AI Initiative.

Can I use Apertus just like other AI systems?

Apertus is not a consumer product: this is foundational infrastructure. Designed to support innovation across research, education, government, and industry, while remaining aligned with Swiss and European values of transparency, neutrality, and accountability. Many organizations are currently piloting solutions with the model, and we will update our showcase as new products based on Apertus become available. See also swissinfo 10.2025.

Is Apertus compliant with the EU AI Act?

Apertus is designed with the EU AI Act in mind, including opt-out mechanisms, PII removal, and memorization prevention. An independent evaluation by LatticeFlow AI found Apertus "EU AI Act-ready" and 99% secure with guardrails in place.

Why are some model weights gated?

While the Apertus 1.5 release remains fully open in its development process, the gating mechanism on Hugging Face is a legal requirement in order to help make sure that the Usage Terms and other policies are complied with. The approval process is automatic and immediate, not intended to prevent you from downloading the model. Your data will never be used for marketing, or any other purpose.

May I use Apertus commercially?

Yes. Apertus is released under Apache 2.0, allowing both research and commercial use without restrictions or royalties. Use it freely in any project, but abide by license terms and be aware of statutory limitations. Try the Open License Helper.

What languages does Apertus support?

Apertus is trained on 1800+ languages, making it a strong foundation for further development. Currently, Apertus is fully conversational in a few dozen languages. For specific language needs, we encourage users to evaluate or fine-tune Apertus. Refer to the Tech Report for more details.

Can I fine-tune Apertus?

Yes! You can fine-tune Apertus with your own data for specialized tasks (e.g., domain-specific knowledge, proprietary data). Guidance and tools are available in our fine-tuning guide.

How is Apertus aligned?

Apertus was trained with ethical and safety principles to align with public values (e.g., transparency, fairness, human oversight). While we strive to minimize bias, users should be aware of inherent biases in language data and test for fairness in their applications. See the Apertus Charter for details.

Why the name Apertus?

Our identity and domain name reflect the Helvetic-Roman heritage of our nation, and the history of Swiss scholarship. The APERTVS logo was designed by Florian Molinari.

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