---
title: "Parca template variables | Grafana documentation"
description: "Use template variables with the Parca data source in Grafana."
---

# Parca template variables

Instead of hard-coding label values in your profiling queries, you can use template variables to create dynamic, reusable dashboards. Variables appear as drop-down menus at the top of the dashboard, making it easy to switch between services, instances, or environments without editing queries.

For an introduction to template variables, refer to the [Variables](/docs/grafana/next/dashboards/variables/) documentation.

## Supported variable types

Expand table

| Variable type | Supported | Notes                                                                        |
|---------------|-----------|------------------------------------------------------------------------------|
| Custom        | Yes       | Define a static list of values manually.                                     |
| Text box      | Yes       | Enter a free-form value at the top of the dashboard.                         |
| Constant      | Yes       | Define a hidden, fixed value.                                                |
| Data source   | Yes       | Select a data source instance by name.                                       |
| Query         | No        | Parca doesn’t implement variable queries to dynamically populate drop-downs. |

> Note
> 
> Parca doesn’t support query-type variables. You can’t use the Parca data source to dynamically populate variable drop-downs. Use custom variables to define values manually, or use another data source to populate query variables.

## Use variables in the label selector

The Parca query editor’s label selector field supports template variable interpolation. Use the standard `$variablename` or `${variablename}` syntax. Variables are interpolated in the label selector only – the profile type drop-down doesn’t support them.

### Variable syntax options

Expand table

| Syntax                   | Description                                                                      |
|--------------------------|----------------------------------------------------------------------------------|
| `$variablename`          | Simple syntax for most cases.                                                    |
| `${variablename}`        | Use when the variable is adjacent to other text (for example, `${host}_suffix`). |
| `${variablename:format}` | Apply a specific format to the variable value.                                   |

## Example: Filter profiles by service

Create a custom variable to switch between services in your profiling dashboard.

1. Navigate to **Dashboard settings** > **Variables**.
2. Click **Add variable**.
3. Set **Type** to **Custom**.
4. Enter a **Name**, for example `service`.
5. In the **Custom options** field, enter comma-separated values, for example `frontend, backend, api-gateway`.
6. Click **Apply**.

In your Parca query’s label selector, reference the variable:

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

```text
{job="$service"}
```

When you change the drop-down selection, the panel refreshes to show profiles for the selected service.

## Example: Filter by service and instance

Create two custom variables to filter by multiple dimensions.

1. Create a variable named `service` with custom values `frontend, backend, api-gateway`.
2. Create a second variable named `instance` with custom values for your instance addresses, for example `10.0.0.1:7070, 10.0.0.2:7070, 10.0.0.3:7070`.

In your Parca query’s label selector, reference both variables:

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

```text
{job="$service", instance="$instance"}
```

## Example: Use a text box variable for free-form filtering

Create a text box variable for free-form label filtering.

1. Navigate to **Dashboard settings** > **Variables**.
2. Click **Add variable**.
3. Set **Type** to **Text box**.
4. Enter a **Name**, for example `label_filter`.
5. Optionally set a default value, for example `job="my-service"`.
6. Click **Apply**.

In your Parca query’s label selector, reference the variable:

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

```text
{$label_filter}
```

This lets you type any label matcher directly into the variable input at the top of the dashboard without editing the panel query.

## Limitations

Parca template variable support has the following limitations:

- **No query variable support:** You can’t use Parca as a data source for populating variable options. Define values manually with custom variables or use another data source.
- **Label selector only:** Variables are interpolated in the label selector field. The profile type drop-down doesn’t support variables.
- **No free-form filters:** Parca doesn’t support [free-form filters](/docs/grafana/next/dashboards/variables/add-template-variables/#add-ad-hoc-filters).

## Next steps

- [Build queries](/docs/grafana-cloud/connect-externally-hosted/data-sources/parca/query-editor/) using your template variables.
- [Troubleshoot issues](/docs/grafana-cloud/connect-externally-hosted/data-sources/parca/troubleshooting/) if queries aren’t returning expected data.