> ## Documentation Index
> Fetch the complete documentation index at: https://docs.honeycomb.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Send Application Metrics to Honeycomb

> Instrument your application with OpenTelemetry SDKs to create counters, histograms, and gauges, and send metrics to Honeycomb for analysis.

## How It Works

OpenTelemetry SDKs are implemented and stable for several languages.
They provide an API, which allows your application to create custom metrics with **metrics instruments** like counters, histograms, and gauges.
Instrumentation libraries used in different languages can also capture metrics from the application's runtime environment, such as the number of HTTP requests served by an HTTP server.
OpenTelemetry SDKs can then be configured to send metrics to Honeycomb over OpenTelemetry Protocol (OTLP).

```mermaid actions={false} theme={}
flowchart LR
  subgraph S["Instrumented App"]
    A("OpenTelemetry SDK")
  end
  A -->|OTLP| B("Honeycomb")
```

## Instrumenting Your Application

Refer to the [OpenTelemetry SDK Documentation for your environment](https://opentelemetry.io/status/) for details on how to instrument your application.
You will need to enable an OTLP exporter and it should have:

* a destination of:
  * for our US instance: `api.honeycomb.io:443`
  * for our EU instance: `api.eu1.honeycomb.io:443`
* an `x-honeycomb-team` header with an API key that has write permissions
* an `x-honeycomb-dataset` header with the name of the dataset you would like to send metrics to

## Troubleshooting Metrics

### Metrics Sent to `unknown_metrics`

If using Honeycomb and a metrics dataset is not specified, all metrics data will be sent to a dataset called `unknown_metrics`.
Once you specify a metrics dataset, all metrics data will be sent to that dataset.

<Info>
  This troubleshooting scenario is not applicable to [Honeycomb Classic users](/troubleshoot/product-lifecycle/recommended-migrations/#migrate-from-honeycomb-classic-to-honeycomb-environments).
</Info>