Claude Opus 5 (Fast) vs Kimi K3: side-by-side summary

Claude Opus 5 (Fast) and Kimi K3 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

Claude Opus 5 (Fast), from Anthropic, has a 1,000,000-token context window and is priced at $10/M tokens input, $50/M tokens output on OpenRouter.

Kimi K3, from moonshotai, has a 1,048,576-token context window and is priced at $2.40/M tokens input, $12/M tokens output on OpenRouter.

Context window

• Claude Opus 5 (Fast): 1,000,000 tokens
• Kimi K3: 1,048,576 tokens

Price

• Claude Opus 5 (Fast): $10/M tokens input, $50/M tokens output
• Kimi K3: $2.40/M tokens input, $12/M tokens output

Provided by

• Claude Opus 5 (Fast): Anthropic
• Kimi K3: moonshotai

• Claude Opus 5 (Fast) model details, providers and pricing
• Kimi K3 model details, providers and pricing