# Muse Spark Open

Muse Spark Open is Meta's latest language model in our dataset, released Oct 15, 2026. Open weights (Muse Model License (limited commercial terms)). Meta's open-weights 816B-parameter mixture-of-experts model (42B active), released Oct 15, 2026 under the Muse Model License, which has limited commercial terms. Verified against vendor sources on Oct 26, 2026.

Last verified: 2026-10-26 · Evidence: Reported · Canonical: https://theagenticweekly.com/models/muse-spark-open · JSON: https://theagenticweekly.com/api/models/muse-spark-open

## Key facts

| Fact | Value | Source |
|---|---|---|
| Vendor | Meta |  |
| Released | Oct 15, 2026 | https://research.meta.ai/blog/muse-spark-open |
| Context window | 1,000,000 tokens (1M) | https://research.meta.ai/blog/muse-spark-open |
| Input | text, image, video, audio | https://research.meta.ai/blog/muse-spark-open |
| Output | text | https://research.meta.ai/blog/muse-spark-open |
| Parameters | 816B total, 42B active, mixture-of-experts, 256 experts, 8 active | https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B |
| Licence | Muse Model License (limited commercial terms) (open weights). Not an OSI-approved open-source license; read the terms before commercial use. | https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B |

## Vendor claims and neutral signals

- Needs about 700 GB of VRAM for the NVFP4 checkpoint and about 2 TB for BF16, per Meta; it is not a laptop model.

## Notes

- Meta lists hosted access at Baseten, Fireworks, Groq, Modal, Nebius, OpenRouter and Together; prices are set by those providers.

## What we tested

Nothing yet. We have not run Muse Spark Open ourselves, so every fact here is Reported from the sources below.

## Not verified, left out

- Meta's own API price: not stated by Meta. Meta's proprietary Muse Spark 1.x models appear on public leaderboards but we did not verify their specifications; Muse Wonder is listed separately.

## Sources

- [Meta research blog](https://research.meta.ai/blog/muse-spark-open)
- [Hugging Face model card](https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B)

Data licence: CC BY 4.0. Data: Agentic Weekly (https://theagenticweekly.com), CC BY 4.0.