Models
What Is Muse Spark Open? Meta’s Open-Weight Model, Explained
Muse Spark Open is Meta’s new open-weight AI model, released October 15, 2026. Is it open source, can it run on a Mac, and how it compares to Muse Wonder.
Muse Spark Open is a free-to-download AI model that Meta released on October 15, 2026. It is the first big model Meta has given away since its Llama series, and it came with a surprise partner: Apple, which helped make it run on Mac computers.
If you saw "Meta Muse Spark Open" in the news and wondered what it is, whether it is really open source, and if you can use it, here are the plain answers.
What is Muse Spark Open?
Meta’s AI lab, Meta Superintelligence Labs, launched a model called Muse Spark on April 8, 2026. That one was closed: you could only use it inside Meta’s apps and services. Muse Spark Open is the version you can download.
It is a very large model. It has 816 billion parameters in total, but it only uses about 42 billion of them for each word it writes. This design is called "mixture of experts." Think of a big office where only the right few specialists answer each question. It keeps the model faster and cheaper to run than its size suggests.
Meta says the model can read text, images, video, and audio, and it can take in up to 1 million tokens at once. That is enough for several long books in one go. Meta built it mainly for agent work, like coding and customer service agents. Meta calls it the most capable US open-weight model so far.
| Fact | Muse Spark Open |
|---|---|
| Made by | Meta (Meta Superintelligence Labs) |
| Released | October 15, 2026 |
| Size | 816B total parameters, about 42B active per token |
| Context window | 1 million tokens |
| Inputs | Text, image, video, audio |
| License | Muse Model License (free, with conditions) |
| Where to get it | Hugging Face, Amazon SageMaker AI, Google Cloud Model Garden, Microsoft Foundry |
| Hosted APIs | Baseten, Fireworks AI, Groq (limited preview), Modal, Nebius, OpenRouter, Together AI |
Is Muse Spark Open open source?
Not quite, and this is the most searched question about it. The model’s "weights," the files that hold what it learned, are public. You can download them, run them, fine-tune them, and even sell products built on them. Meta does not claim ownership of what the model writes.
But the license is Meta’s own, not a standard open-source one like MIT or Apache. According to reporting on the license, it has two main rules:
- Apps and services that use it must show the label "Built with Muse Spark Open."
- Companies with more than $20 million in yearly revenue that want to sell it as an API service need a separate deal with Meta.
Downloading from Hugging Face also needs a short access form. So the fair label is "open weight." For comparison, the DeepSeek V4.1 Flash files are under the MIT license, which has fewer strings.
Can Muse Spark Open run on a Mac?
Yes, but not on a normal one. This is where Apple comes in. Meta and Apple worked together so the model runs locally with Apple’s MLX software on Mac Studio computers with the M5 Ultra chip. Meta’s developer guide lists two setups:
- Two Mac Studios with 512GB of memory each, or
- Four Mac Studios with 256GB of memory each.
The machines are linked with Thunderbolt 5 cables and share the work. That is still a lot of money, but it is the first time a model of this class runs on desktop computers at all, not just in data centers. Meta’s compressed NVFP4 version is about 530GB, and the full version is about 1.6TB.
CNBC and Axios both covered the partnership as a notable truce between two companies that have often clashed. The deal is also framed as a US answer to free Chinese models. Meta itself compares Muse Spark Open with Qwen 3.8, GLM 5.3, and Kimi K3.
Muse Spark Open vs Muse Wonder
Meta now has several Muse models, and the names are easy to mix up. Here is how they fit together.
| Model | Can you download it? | How Meta positions it |
|---|---|---|
| Muse Spark | No | Meta’s first closed frontier model, launched April 2026 |
| Muse Spark Open | Yes | The open-weight version, released October 15, 2026 |
| Muse Wonder | No | Meta’s newer, stronger paid models, introduced October 12, 2026 |
Meta says Muse Spark Open beats Qwen 3.8, GLM 5.3, and Kimi K3 in several areas, including agent tasks and reasoning, but trails some rivals on coding and stays well short of Muse Wonder Full. Those are Meta’s own tests. An early independent ranking from Vals.ai put it 38th of 49 models on its Vals Index, with a score of 46.61%. More testing will follow.
What this means for you
For most people, Muse Spark Open is something you will feel, not touch. You will not run an 816 billion parameter model on your phone. What changes is that strong AI keeps getting cheaper and more widely available, and that shows up later inside the apps you already use.
It also confirms the trend we keep seeing. Meta did not pitch this as a better chatbot. It pitched it as a model for agents: the kind of AI that picks the right tool, works through steps, and finishes a job. That is what agentic AI means.
And the model list keeps growing. This week alone brought Muse Wonder, Muse Spark Open, and a DeepSeek update. You do not need to follow every release to get the benefit. Our app, Agentic AI, gives you a team of ready-made expert agents on iPhone and iPad, like a Research Analyst, a Writing Coach, and a Code Helper. Give a task to one agent or put up to 4 on it together. There is no account to make, and you get 3 free tasks to try it. If you are new to agents, our guide to how AI agents work is a good start.
Quick answers
When was Muse Spark Open released? Meta released it on October 15, 2026.
Is Muse Spark Open free? The weights are free to download and use under the Muse Model License. Large companies selling it as an API need a deal with Meta. Hosted APIs like OpenRouter and Together AI charge their own prices.
Is Muse Spark Open on Hugging Face? Yes. The official repo is meta-models/Muse-Spark-Open-816B-A42B, and it requires an access form. Community builds for llama.cpp and Unsloth also exist.
Can I run Muse Spark Open with Ollama? Not on an average computer. Even the smallest community versions need roughly 256GB to 300GB of memory, according to Meta’s developer guide.
Is Muse Spark Open better than Muse Wonder? No. Meta says it falls well short of Muse Wonder Full. Muse Spark Open’s advantage is that you can download and run it yourself.
Sources: Meta: Build with Muse Spark Open · Hugging Face model card · CNBC · Axios · The Decoder · Vals.ai
