Meta Releases Weights for Muse Spark Open

Meta Releases Weights for Muse Spark Open — 816B Parameter MoE

On October 15, 2026, Meta released the weights for Muse Spark Open — a natively multimodal MoE model with 816 billion parameters (42 billion active per token) and a 1 million token context window, which the company calls the most powerful open model in the US.

Compiled by Sergey KostenchukPublished 2026-10-15Updated 2026-10-15

2026-10-15 Research Google

🤖 Meta Releases Weights for Muse Spark Open — 816B Parameter MoE

The model was released on October 15, 2026: 42 billion parameters are activated per token, with a 1 million token context window. It accepts text, images, video, and audio. According to Meta, this is the most powerful open model in the US today.

🌍 For the first time, a model of this class runs without the cloud: it runs entirely on two Mac Studio machines with M5 Ultra via MLX — up to 512 GB of memory per machine and 1.2 TB/s of data exchange. The weights are on Hugging Face (BF16 and NVFP4), and APIs are offered by 7 platforms — from Groq to Together AI.

👤 The weights can be downloaded and run at home via MLX, or tried for free via OpenRouter and Baseten. Note: the Muse Model License has commercial restrictions, and the license text has not been publicly disclosed — check the terms before integrating it into a product.

Source 1: https://research.meta.ai/blog/muse-spark-open

Source 2: https://huggingface.co/collections/meta-models/muse-spark-open

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