Muse: Spark Open API

Meta's Muse: Spark Open, through an OpenAI-compatible API. Providers quote it on an open exchange, and each request goes to the offer with the lowest estimated charge that meets your rules.

Providers compete for each request. The exchange ranks the offers that meet your rules by estimated charge. It fixes your maximum charge before the first token, and you pay for the tokens that the model uses.
The OpenAI and Anthropic APIs. Use the OpenAI or Anthropic SDK that you have. Set the base URL and your key, and send muse-spark-open as the model.
Your data rules. Send x-liquid-retention: none and only offers whose provider does not keep your content compete for the request.

Facts

Model name: muse-spark-open
Maker: Meta
Context window: 1M tokens
Input price: $1.249 per million tokens
Output price: $4.247 per million tokens
Providers: 1 independent provider
Regions: us

Providers

Architect: us, $1.249 input and $4.247 output per million tokens, $0.150 cache read per million tokens, 1M tokens of context

Scores

Intelligence: 24.9, #24 of 41
HLE: 43.9, #22 of 273
GPQA: 89.0, #54 of 250
AA-LCR: 78.3, #65 of 237
SciCode: 58.4, #17 of 123

Scores: Artificial Analysis (https://artificialanalysis.ai/)

Request

curl https://router.inference.ai.exchange/v1/chat/completions \
  -H "Authorization: Bearer $LIQUID_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "muse-spark-open",
    "messages": [{"role":"user","content":"Say hello."}]
  }'

Questions

What is Muse: Spark Open?: Muse: Spark Open is a model from Meta.
How much does Muse: Spark Open cost?: Offers now ask $1.249 per million input tokens and $4.247 per million output tokens. A job pays for the tokens it uses. The exchange picks the cheapest eligible offer.
What is the context length of Muse: Spark Open?: The largest offer takes 1,048,576 input tokens. A smaller offer can take less. The exchange skips an offer that cannot take your message.
What can Muse: Spark Open do?: Its providers list Vision, Reasoning effort, JSON object, JSON schema, Frequency penalty, Logit bias, Log probabilities, Min-p sampling, Presence penalty, Repetition penalty, Seed, Stop sequences, Top-k sampling, Top-p sampling, Text, Tools.
What inputs and outputs does Muse: Spark Open support?: Text · Images → Text.
Which providers serve Muse: Spark Open?: 1 independent provider quote it now, with 1 offer. The table above ranks them by the cost of a typical job.
How do I call Muse: Spark Open?: Send "muse-spark-open" as the model in an OpenAI or Anthropic request. The API section links to setup steps for each client.
When was Muse: Spark Open listed?: The exchange first listed it on 10/15/2026. This is not its release date.