# Muse Spark Open

> Meta's Muse Spark Open is a coding-optimized open-weight model for agentic coding. It is a sparse mixture-of-experts with 816B total and about 42B active parameters, reads text, images, video, audio and files, returns text, and has a 1M-token context window.

**ID**: `meta/muse-spark-open`  
**Creator**: meta  
**Category**: multimodal  
**Context**: 1M tokens  
**Pricing**: $1.25 / $4.25 per 1M · billed by your provider (BYOK)  
**Released**: 2026-10-15  
**Web page**: https://anyrouter.dev/model/meta/muse-spark-open

**Input modalities**: text, image, video, file, audio  
**Output modalities**: text  

**Capabilities**: chat, reasoning, streaming, function-calling, vision, coding, agentic

**Supported parameters**: frequency_penalty, include_reasoning, logit_bias, logprobs, max_tokens, min_p, presence_penalty, reasoning, reasoning_effort, repetition_penalty, response_format, seed, stop, structured_outputs, temperature, tool_choice, tools, top_k, top_logprobs, top_p

## Usage

**Endpoint**: `POST https://anyrouter.dev/api/v1/chat/completions`

```bash
curl https://anyrouter.dev/api/v1/chat/completions \
  -H "Authorization: Bearer $ANYROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "meta/muse-spark-open",
  "messages": [
    {
      "role": "user",
      "content": "Say hi in 3 words."
    }
  ]
}'
```

## Providers

| Provider | Input | Output |
| --- | --- | --- |
| openrouter-byok | $1.25/M (list) | $4.25/M (list) |

BYOK routes are billed by your own provider key — AnyRouter charges $0. Rates marked (list) are the provider's published list price.

## Model card

- Architecture: mixture of experts [1]
- Total parameters: 816B [1]
- Active parameters: 42B [1]
- License: Muse Model License, open weights (https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B) [1]

### Links

- model card: https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B

### Sources

1. [Muse Spark Open model card and Muse Model License (Hugging Face, Meta)](https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B) (accessed 2026-10-17)

## Source

- Upstream docs: https://huggingface.co/meta-models/Muse-Spark-Open-816B-A42B