Muse Spark 1.2 vs Grok 4.5

Muse Spark 1.2 and Grok 4.5 are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Muse Spark 1.2, from Meta, has a 1,048,576-token context window, costs $1.25/1M input and $4.25/1M output tokens and scores 39.6 on the Artificial Analysis Intelligence Index.

Grok 4.5, from xAI, has a 500,000-token context window, costs $2.00/1M input and $6.00/1M output tokens and scores 38.8 on the Artificial Analysis Intelligence Index.

Muse Spark 1.2 is the cheapest on input, 1.6× cheaper than the next model, Muse Spark 1.2 has the largest context window, Muse Spark 1.2 scores highest for intelligence and Grok 4.5 leads on coding.