Claude Opus 5 (Fast) vs Granite 4.2 8B: side-by-side summary

Claude Opus 5 (Fast) and Granite 4.2 8B 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.

Granite 4.2 8B, from ibm-granite, has a 131,072-token context window and is priced at $0.10/M tokens input, $0.15/M tokens output on OpenRouter.

Context window

• Claude Opus 5 (Fast): 1,000,000 tokens
• Granite 4.2 8B: 131,072 tokens

Price

• Claude Opus 5 (Fast): $10/M tokens input, $50/M tokens output
• Granite 4.2 8B: $0.10/M tokens input, $0.15/M tokens output

Provided by

• Claude Opus 5 (Fast): Anthropic
• Granite 4.2 8B: ibm-granite

• Claude Opus 5 (Fast) model details, providers and pricing
• Granite 4.2 8B model details, providers and pricing