Meta ships Muse Spark Open, open-weight model with 816B parameters

Meta is returning to open-weight territory after its Llama series. The company is positioning Muse Spark Open as its answer to Chinese open-weight competitors such as Qwen, GLM, and Kimi, which have set the pace in that segment.

The model is optimized to run locally on Apple's M5 Ultra and on two Mac Studios with 512 GB of unified memory each, according to Meta. Weights are available on Hugging Face. Meta says Muse Spark Open leads in Agentic, Knowledge & Reasoning, and Multimodal categories but falls behind some competitors on coding benchmarks. The license is free to use with a "Built with Muse Spark Open" label, and providers earning more than $20 million a year that want to resell it as an API service need a separate agreement with Meta.

The benchmark comparison puts Muse Spark Open ahead of Qwen 3.8, GLM 5.3, and Kimi K3 in several categories, but Meta says the model still falls well short of its own paid Muse Wonder Full models. That gap suggests Meta is keeping its strongest capabilities behind a paid tier while offering the open-weight version as a competitive option for local use and coding tasks.