What is OpenRouter?
The Harvard Chan AI Glossary
In our classes, we often pause to explain the ideas behind AI and the language used to describe it. These posts grew out of those conversations. They’re for anyone who would like to understand AI better, with no technical background assumed.
OpenRouter is a service that gives applications a common API for accessing models from multiple providers and routing requests to supported model services. An API, or application programming interface, is an agreed way for software to send requests and receive responses. Routing means deciding where a request is sent.
This adds a layer between the application and the service running the model. The model developer, the provider executing the model and the application used by the person may be different organizations. A common connection format can make access easier without making those roles identical.
For example, Goose can connect to a DeepSeek model through OpenRouter. Goose is the agent environment, DeepSeek identifies the model and OpenRouter provides the access route. The example is useful because it names the three choices separately rather than treating the whole arrangement as a single product.
An illustrative benefit is that a developer can compare supported models without writing an entirely separate connection for each provider. The surrounding application can supply a similar task through a common interface. Model-specific behavior and supported features can still differ, so a common API does not guarantee identical results or settings.
Routing also has consequences for information handling. The application sends material to the service involved in processing the request. Which provider receives it, what happens if one provider is unavailable and what records are retained depend on the configuration and service arrangements. Those questions need to be examined rather than inferred from the selected model name.
A fallback is an alternative used when the preferred service cannot complete a request. It can improve continuity, but may also change the model or provider behind the response if the setup allows it. For a controlled comparison, it is important to know what actually ran.
OpenRouter is therefore not itself one model, nor a substitute for the application’s permissions and checks. It is a model-access and routing service. Understanding that role helps a user ask the right questions about capability, cost and where information travels through the complete system.
Source: OpenRouter — Quickstart and Provider Routing Documentation.
If you would like to find out more about AI and improve your leadership skills, consider the AI in Health Care Certificate of Specialization from the Advanced Learning Academy at Harvard T.H. Chan School of Public Health. You can take an individual course or work toward the full certificate.
AI is a fast-moving field. This explanation reflects our class discussions and related material at the time of writing. Terminology, capabilities and tools may change.
For suggested additions or corrections, please email me at tpanch@hsph.harvard.edu.
Dr. Trishan Panch
Program Director, AI in Health Care
Harvard T.H. Chan School of Public Health — Advanced Learning Academy