Meta Releases Muse Spark Open: 816B Open-Weight MoE Model With 1M Context Window

Meta has released Muse Spark Open, an 816-billion-parameter open-weight mixture-of-experts model featuring a 1-million-token context window. The release makes one of the largest openly available MoE architectures accessible to developers and researchers without API restrictions. Meta and Apple have also collaborated to optimize Muse Spark Open for the MLX framework, enabling efficient local inference on Apple Silicon Macs. For developers, this means a frontier-scale open-weight model is now runnable locally on consumer hardware, lowering the barrier to building large-context applications. This is a significant shift in the open-weight landscape, putting Meta's most capable model in direct reach of teams without large cloud budgets.