Claude Opus 5 (Fast) vs Gemini 3.6 Flash: side-by-side summary

Claude Opus 5 (Fast) and Gemini 3.6 Flash 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.

Gemini 3.6 Flash, from Google, has a 1,048,576-token context window and is priced at $0.75/M tokens input, $3.75/M tokens output on OpenRouter.

Context window

• Claude Opus 5 (Fast): 1,000,000 tokens
• Gemini 3.6 Flash: 1,048,576 tokens

Price

• Claude Opus 5 (Fast): $10/M tokens input, $50/M tokens output
• Gemini 3.6 Flash: $0.75/M tokens input, $3.75/M tokens output

Provided by

• Claude Opus 5 (Fast): Anthropic
• Gemini 3.6 Flash: Google

• Claude Opus 5 (Fast) model details, providers and pricing
• Gemini 3.6 Flash model details, providers and pricing