Unofficial guide. Not affiliated with Meta.
Last verified: 21 October 2026
Muse Spark Open’s weights are genuinely free to download – that part of the story is simple. What is not simple is running them: this is an 816B-parameter model whose smaller checkpoint is about 530GB. This guide covers where the weights live, how big they are, and the three routes people actually use – without inventing install steps that do not exist in the record.
Where to get it
- Hugging Face – the weights are free to download from meta-models/Muse-Spark-Open-816B-A42B.
- Cloud model gardens – Spark Open is also available via Amazon SageMaker, Google Cloud Model Garden and Microsoft Foundry.
- Hosted APIs – it was live on hosted providers from day zero (see route 2 below).
The size warning, plainly
There are two checkpoints. The BF16 checkpoint is about 1.6TB; the NVFP4 checkpoint is about 530GB. Downloading either is a serious transfer, storing it needs a serious drive, and running it needs roughly as much memory as the checkpoint size – about 1,600GB for BF16 or about 530GB for NVFP4. Normal home computers cannot run this model. Before downloading anything, check your hardware with the Can I Run It? hardware checker.
The three realistic routes
1. Download and run locally – only with very large memory
This route is real but narrow: you need memory in the hundreds of gigabytes for NVFP4, or around 1.6TB for BF16. The public demonstration of local running, from Meta and Apple, used two 512GB M5 Ultra Mac Studios – machines that are not yet shipping. If your hardware is not in that class, this is not your route.
2. Hosted APIs – the day-zero route most people use
Spark Open launched on hosted APIs from day zero: Baseten, Fireworks AI, Groq, Modal, Nebius, OpenRouter and Together AI. You call the model over the provider’s API and pay per token instead of owning the hardware problem. OpenRouter has been cited at $1.25 per 1M input tokens (reported).
3. Cloud model gardens
The same weights are also reachable through Amazon SageMaker, Google Cloud Model Garden and Microsoft Foundry, for teams already running on those clouds.
Licence
Spark Open is released under the Muse Model License – free for most uses. The exception that matters commercially: large API hosts (over $20M in revenue) need a separate deal. If you plan to resell access at scale, read the licence before you build on it.
For the model in context – and how it differs from Muse Wonder and Muse Spark – see What Is Muse Wonder? Meta’s New AI Model Explained. For how the free routes compare across the October launches, see Free Alternatives to Muse Wonder, Gemini 4 Argon and FLUX 3 Max.
Last verified: 21 October 2026
Unofficial guide. Not affiliated with Meta.