# Meta’s Muse Spark Open launches on Fireworks’ US serverless API

> Fireworks says Meta’s 816-billion-parameter open-weights model is available on US-only serverless capacity, with no US premium.

Oossa · 2026-10-23 · https://oossa.com/en/meta-s-muse-spark-open-launches-on-fireworks-us-serverless-api

Fireworks AI says Meta’s Muse Spark Open is available through its serverless API on US-only capacity, with no US premium. The open-weights model has 816 billion total parameters, 42 billion active per token, and a 1-million-token context window.

Fireworks reports that the model ranked first on Vals AI’s Harvey Legal Agent Benchmark, scoring 25.4% across 75 models. The company also cites results from its own evaluations and other benchmarks; performance can depend on the test setup, and the post does not provide current API pricing.

## The facts

- Fireworks reports a 25.4% score on Harvey Legal Agent Benchmark, ranking first among 75 models.
- The model has 816 billion total parameters and a 1-million-token context window.

## Why it matters

US-based organizations considering open-weight models can access Muse Spark Open on Fireworks’ US-only serverless capacity, but they should check current pricing and evaluate it on their own workflows.

## Sources & references

1. [Muse Spark Open on Fireworks: Meta’s open weights wodel, available on US serverless](https://fireworks.ai/blog/meta-muse-spark-open/) – Fireworks AI

Last updated: 2026-10-23