OpenRouter Fusion API

OpenRouter has launched Fusion API, which introduces a multi-model deliberation approach to overcome the performance limits of a single model. This approach works on the principle that multiple expert models analyze a single prompt in parallel, and a judge model structures the consensus, contradictions, and unique insights among the outputs to compose the final answer.

The key features are as follows:

• Performance improvement: According to DRACO benchmark results, fusing multiple models consistently outperformed individual models (Fable 5, GPT-5.5, etc.).
• Flexible configuration: It offers a quality-focused Quality preset and a Budget preset for cost savings, and users can redefine the panel models and judge model themselves.
• Cost structure: Pricing is based on the sum of completion costs of all executed models, rather than a single model call.
• Suitable use cases: Recommended for research, expert critique, or precise tasks requiring high accuracy where the cost of a wrong answer is greater.

Users can use it directly in Chatroom without code changes, or integrate the API in various ways such as Model slug, Server tool, and Plugin.