Claude Sonnet 5 vs Kimi K3

Claude Sonnet 5 and Kimi K3 are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Sonnet 5, from Anthropic, has a 1,000,000-token context window, costs from $2.00/1M input and $10.00/1M output tokens across 2 providers and scores 38.2 on the Artificial Analysis Intelligence Index.

Kimi K3, from MoonshotAI, has a 1,048,576-token context window, costs from $2.70/1M input and $13.50/1M output tokens across 4 providers and scores 43.6 on the Artificial Analysis Intelligence Index.

Claude Sonnet 5 is the cheapest on input, 1.4× cheaper than the next model, Kimi K3 has the largest context window, Kimi K3 scores highest for intelligence, Kimi K3 leads on coding and Claude Sonnet 5 has the highest throughput.