OpenRouter Launches 'Fusion,' a Compound-Model API That Beats Frontier Models at Roughly Half the Cost

OpenRouter Blog·high signal

OpenRouter released Fusion, a compound API that fans each prompt out to a panel of models, synthesizes their answers, and returns one response. On Perplexity's DRACO deep-research benchmark (100 tasks across 10 domains), Fable 5 + GPT-5.5 fused scored 69.0% versus 65.3% for Fable 5 alone, and a budget panel of Gemini 3 Flash + Kimi K2.6 + DeepSeek V4 Pro beat solo GPT-5.5 and Opus 4.8 at about half Fable 5's price — though calls run 2-3x longer.