Kimi K2 Thinking vs Grok 4 Fast: side-by-side summary

Kimi K2 Thinking and Grok 4 Fast are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

Kimi K2 Thinking, from moonshotai, has a 262,144-token context window and is priced at $0.60/M tokens input, $2.50/M tokens output on OpenRouter.

Grok 4 Fast, from SpaceXAI, has a 2,000,000-token context window and is priced by the provider serving it on OpenRouter.

Context window

• Kimi K2 Thinking: 262,144 tokens
• Grok 4 Fast: 2,000,000 tokens

Price

• Kimi K2 Thinking: $0.60/M tokens input, $2.50/M tokens output
• Grok 4 Fast: Pricing varies by provider

Provided by

• Kimi K2 Thinking: moonshotai
• Grok 4 Fast: SpaceXAI

• Kimi K2 Thinking model details, providers and pricing
• Grok 4 Fast model details, providers and pricing