GPT-5.6 Sol Pro vs Fugu Ultra: side-by-side summary

GPT-5.6 Sol Pro and Fugu Ultra are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

GPT-5.6 Sol Pro, from OpenAI, has a 1,050,000-token context window and is priced at $2.50/M tokens input, $15/M tokens output on OpenRouter.

Fugu Ultra, from sakana, has a 1,000,000-token context window and is priced at $5/M tokens input, $30/M tokens output on OpenRouter.

Context window

• GPT-5.6 Sol Pro: 1,050,000 tokens
• Fugu Ultra: 1,000,000 tokens

Price

• GPT-5.6 Sol Pro: $2.50/M tokens input, $15/M tokens output
• Fugu Ultra: $5/M tokens input, $30/M tokens output

Provided by

• GPT-5.6 Sol Pro: OpenAI
• Fugu Ultra: sakana

• GPT-5.6 Sol Pro model details, providers and pricing
• Fugu Ultra model details, providers and pricing