§03 · License explained
The Muse Model License explained. Can you use Muse Spark Open commercially?
This is a summary, not legal advice. Read the full license on Hugging Face before commercial use, and talk to a lawyer if in doubt.
Muse Spark Open ships under Meta’s own Muse Model License, not Apache 2.0 or MIT. It’s free for most developers, but there are three conditions to know about up front.
Condition 1: attribution (Section 2)
Every product or service that uses Muse Spark Open or a derivative (fine-tunes included) must prominently display “Built with Muse Spark Open” in one of:
- the user interface
- the accompanying documentation
- the website
- the settings menu
Condition 2: the $20M threshold (Section 3)
You must notify Meta and sign a separate written agreement only when both are true:
- You offer the model as a service (MaaS)
- You and your affiliates exceed $20 million in gross revenue over any 12 consecutive months
These uses are excluded from the threshold:
- Internal use
- Research
- Using the model as a component of your own product, as opposed to selling model access as a service
| Situation | Separate agreement? |
|---|---|
| Indie developer shipping an app | No |
| $5M-revenue startup selling an API | No |
| $500M-revenue company deploying internally | No |
| $500M-revenue cloud selling inference | Yes |
Condition 3: age
The model card says the model is not intended for people under 18. Products aimed at minors need extra review.
Output ownership (Section 4)
Meta claims no ownership of what the model generates.
How it differs from Muse Glimmer
The smaller Muse Glimmer (30B) is Apache 2.0, with no revenue threshold and no attribution requirement. If licensing matters most, see Compare & choose.
FAQ
Q.Can a small company use Muse Spark Open commercially for free?
A.In most cases, yes. You only need to notify Meta and sign a separate agreement when you offer the model as a service (MaaS) and you and your affiliates exceed $20 million in gross revenue over any 12 consecutive months.
Q.Who owns the output?
A.Section 4 of the license says Meta claims no ownership of outputs generated by the software.
Q.Do I need to credit the model?
A.Yes. Any product or service that uses the model or a derivative must prominently display "Built with Muse Spark Open" in its UI, documentation, website or settings menu.