# Register your own Applications

External applications are your custom applications that are deployed outside of Lenses, for example a Java Kafka Streams or Python Application.

External apps are added to the [Broken mention](broken://pages/Fa3SDemoRRoyTnz6L1y6)

To listing External Apps, Select the `Apps` option from the left sidebar, either open the listing for `External Apps` or expand the node. The tree panel provides oa summary of apps and their status, you can expand further or use the listing

<figure><img src="/files/7Jv28lBUoAE49Uvzjtg3" alt=""><figcaption></figcaption></figure>

#### What your application must expose

Each runner must expose an HTTP(S) health check endpoint at the URL you registered. The contract is:

* Lenses periodically sends a GET request to the URL.
* Return a 2xx status code when the runner is healthy. Any non-2xx response or connection failure marks the runner as Unknown.
* The response body is ignored -- no specific format or content is required.
* If your endpoint requires authentication, embed Basic Auth credentials in the URL (e.g. `https://user:pass@myapp.example.com/health`). Lenses will extract them and send an `Authorization` header.
* HTTPS endpoints are supported; certificate validation is not enforced.

A minimal implementation is an endpoint like `GET /health` that returns `200 OK` when the application is running.


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