Open-weights models
Also written: Open-source models, Open models
AI models with publicly released architecture and parameters, allowing inspection, modification, and use by anyone.
Open-weights models are artificial intelligence systems where the creators share the internal workings, like the code and the learned parameters (weights). This means anyone can download, examine, and even change these models.
For example, a researcher could take an open-weights language model and fine-tune it on a specific type of text, like medical journals, to make it better at understanding medical topics. This contrasts with closed models, where the internal details are kept secret by the company that built them.
Open-weights models, also known as open-source AI models, are characterized by the public release of their architecture and trained parameters (weights). This transparency allows for broad community access, enabling researchers and developers to inspect, modify, replicate, and build upon the models. The primary tradeoff involves potential risks related to misuse and the challenges of ensuring safety and responsible deployment, balanced against benefits like accelerated innovation, wider accessibility, and increased scrutiny.
Open-weights models are a current topic as companies debate their benefits and risks. While some labs release them to promote accessibility and innovation, others express concerns about safety and potential misuse, especially with more powerful models.
- Strengthening our defenses against distillation attacksAnthropic · Anthropic Research ·
- Superintelligence is a dragonMeta · Platformer ·
- Our position on open-weights modelsAnthropic · Anthropic News ·
- Open Weights and AI for AllOpenAI · OpenAI News ·
- Open-sourcing circuit-tracing toolsAnthropic · Anthropic Research ·
- Anthropic Claude
- Anthropic supports open-weights models but emphasizes the need for safety testing and controls on powerful hardware.
- Meta Meta AI
- Meta's vision includes open-weights models as part of its positive AI future.
- OpenAI ChatGPT
- OpenAI has released advanced open-weights models to improve global AI access and build democratic AI infrastructure.
- Open-source software
- Open-source software refers to publicly available code for
- Publicly available APIs
- APIs allow access to a model's functionality but do not
- Research releases
- Some companies release research papers describing models with
The term 'open-weights' emerged from the AI community as a descriptor for models where the trained parameters, or weights, are made publicly accessible, distinguishing them from models where only the architecture or code might be shared, or where everything is proprietary.
You can explore open-weights models by visiting platforms like Hugging Face. Search for a popular open-weights model, like Llama 3, and read about its capabilities. You can then find links to download the model weights or try a demo version if available.
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Questions people ask
- What are model weights?
- Model weights are numerical parameters learned by an AI model during training. They represent the strength of connections between artificial neurons and are crucial for the model's performance.
- Are open-weights models always free to use?
- While the weights are publicly available, the specific license under which they are released determines the terms of use, which may include commercial restrictions or requirements for attribution.
First seen on Subvolts May 29, 2025. Updated Oct 12, 2026. Written by an AI model from the items above and reviewed against them weekly; report an error.