---
title: "prometheus.echo | Grafana Cloud documentation"
description: "Learn about prometheus.echo"
---

> For a curated documentation index, see [llms.txt](/llms.txt). For the complete documentation index, see [llms-full.txt](/llms-full.txt).

# `prometheus.echo`

The `prometheus.echo` component receives Prometheus metrics and writes them to `stdout` in Prometheus exposition format. This component is useful for debugging and testing the flow of metrics through a pipeline. You can place `prometheus.echo` at any stage in your pipeline to inspect the metrics passing through it.

You can specify multiple `prometheus.echo` components by giving them different labels.

## Usage

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
prometheus.echo "<LABEL>" {
}
```

## Arguments

You can use the following arguments with `prometheus.echo`:

Expand table

| Name     | Type     | Description                                                     | Default | Required |
|----------|----------|-----------------------------------------------------------------|---------|----------|
| `format` | `string` | The output format for metrics. Must be `text` or `openmetrics`. | `text`  | no       |

The `format` argument controls how the component encodes metrics when written to `stdout`:

- `text` - Uses the Prometheus text exposition format. This is the default.
- `openmetrics` - Uses the OpenMetrics text format.

If you set any other value, the component logs a warning each time it writes metrics and uses the `text` format.

## Blocks

The `prometheus.echo` component doesn’t support any blocks. You can configure this component with arguments.

## Exported fields

The following fields are exported and can be referenced by other components:

Expand table

| Name       | Type              | Description                                               |
|------------|-------------------|-----------------------------------------------------------|
| `receiver` | `MetricsReceiver` | A value that other components can use to send metrics to. |

## Component health

`prometheus.echo` is only reported as unhealthy if its configuration can’t be evaluated, for example because an argument has the wrong type. In those cases, exported fields retain their last healthy values.

An unrecognized `format` value doesn’t make the component unhealthy. The component uses the `text` format instead.

## Debug information

`prometheus.echo` doesn’t expose any component-specific debug information.

## Debug metrics

`prometheus.echo` doesn’t expose any component-specific debug metrics.

## Example

This example creates a metrics generation and inspection pipeline:

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
prometheus.exporter.unix "default" {
}

prometheus.scrape "demo" {
  targets    = prometheus.exporter.unix.default.targets
  forward_to = [prometheus.echo.debug.receiver]
}

prometheus.echo "debug" {
  format = "text"
}
```

In this example:

1. The `prometheus.exporter.unix` component exposes system metrics.
2. The `prometheus.scrape` component scrapes those metrics.
3. The `prometheus.echo` component receives the scraped metrics and writes them to `stdout` in Prometheus text format.

When you run this configuration, the component writes metrics to `stdout`, which is useful to:

- Debug metric collection issues
- Verify metric labels and values
- Test metric transformations
- Understand the structure of metrics in your pipeline

### Example with OpenMetrics format

Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```alloy
prometheus.scrape "demo" {
  targets = [
    {"__address__" = "localhost:9090"},
  ]
  forward_to = [prometheus.echo.debug.receiver]
}

prometheus.echo "debug" {
  format = "openmetrics"
}
```

This example outputs metrics using the OpenMetrics format instead of the traditional Prometheus text format.

## Compatible components

`prometheus.echo` has exports that can be consumed by the following components:

- Components that consume [Prometheus `MetricsReceiver`](/docs/grafana-cloud/send-data/alloy/reference/compatibility/#prometheus-metricsreceiver-consumers)

> Note
> 
> Connecting some components may not be sensible or components may require further configuration to make the connection work correctly. Refer to the linked documentation for more details.