Open sourceMuse Spark Open: Meta releases open weights under its own license
Meta has released the weights of Muse Spark Open, an 816B-parameter model. Its license requires a notice in every product that uses it, and a separate agreement from anyone offering it as a service with more than $20 million in revenue over 12 months.
Source of truthresearch.meta.ai/blog/muse-spark-openOn October 15, 2026, Meta released the open weights of Muse Spark Open. It is natively multimodal, taking text, images, audio and video, with 816B total parameters (42B active) and a 1M-token context window. The weights are on Hugging Face; API access comes from Together AI, Groq, OpenRouter and others. According to Together AI, its price is $1.25 per 1M input tokens and $4.25 per 1M output tokens. The Muse Model License requires a “Built with Muse Spark Open” notice, and anyone offering the model as a service with more than $20 million in revenue over 12 months must sign a separate agreement with Meta.
Other sources: huggingface.co/blog/meta-muse-spark-openhuggingface.co/…/Muse-Spark-Open-816B-A…together.ai/blog/meta-muse-spark-open
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