Apertus 1.5 70B is Switzerland's latest fully open multilingual large language model developed by the Swiss AI Initiative. It is designed to advance transparent, compliant, and high-performance AI while remaining fully open throughout the entire training pipeline.

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• Swiss AI Initiative : Developed by the Swiss AI Initiative to provide a fully open, transparent, and compliant foundation model.
• Fully Open : Open model weights, open training data, complete training recipes, and publicly documented training methodology.
• Massively Multilingual – Native support for 1,811 languages, enabling broad multilingual understanding and generation.
• Compliance First – Trained using fully compliant datasets while respecting retrospective opt-out requests and reducing memorization through the Goldfish loss methodology.
• Long Context – Supports context windows of up to 262,144 tokens, enabling large document analysis and extended conversations.
• Tool Calling Support – Supports agentic workflows and tool use when deployed with compatible inference frameworks such as recent versions of vLLM.
• Open Deployment Ecosystem – Compatible with Transformers, vLLM, SGLang, MLX and GGUF deployment formats.