OpenRouter, a model aggregation service, continuously runs dynamic routing tests on every large language model to find the best performing providers. In its evaluation of Zhipu AI's latest open-source model, GLM-5.2, cloud provider Parasail.io tied with Zhipu's official channel, z-ai, for the top performance spot.
The dynamic routing system automatically selects the best provider for each request. For requests that include tool calling, OpenRouter defaults to automatic routing. For standard chat requests, users must manually enable it by adding :exacto to the model name. The system tests every provider every five minutes, ranking them by performance and reliability, then directs traffic to the fastest and most stable option.
The benchmark uses two evaluation tools. The first is TauBench (also called Top Bench), which simulates an airline customer service scenario to test an AI's ability to perform multi-step tasks like checking a database and booking or canceling tickets. The second is the GPQA science question set, containing PhD-level problems in physics, chemistry, and biology, designed to test complex reasoning. By having different providers' AIs answer these questions, the system measures the real speed and accuracy of each service.