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

# Preview

> Use the Rule Preview card on a rule's detail page to test its saved conditions against recent traces before relying on it

Before you wire a rule into your application, you can sanity-check it against real, recent activity. The **Rule Preview** card sits on a rule's detail page, next to the **Associated Entities** card.

## Running a preview

Click **Run Preview** to test the rule's current *saved* conditions - so save your conditions first, or the preview will run against whatever was last saved rather than your unsaved edits. The button shows "Running…" while it works.

A preview checks your last 100 traces and shows up to the top 5 that matched, each with its service name, span name, trace ID, and a **Matched** / **No Match** badge.

## States you'll see

* Before running it for the first time: "Click 'Run Preview' to test your saved rule conditions against recent traces."
* If none of the last 100 traces matched: "No matching traces found in the last 100 records."

## What preview is - and isn't - for

Preview is a sanity check for building and tuning a rule. It isn't connected to your live application traffic, and running it doesn't affect anything downstream. When your application actually needs to use a rule, it calls the separate [evaluate API](/latest/openlit/prompts-experiments/rule-engine/evaluate-api) - preview is only there to help you confirm a rule's conditions look right before you rely on that API.

***

<CardGroup cols={2}>
  <Card title="Conditions" href="/latest/openlit/prompts-experiments/rule-engine/conditions" icon="filter">
    Build the condition groups you're previewing
  </Card>

  <Card title="Evaluate API" href="/latest/openlit/prompts-experiments/rule-engine/evaluate-api" icon="code">
    Use the rule from your application, once you're happy with it
  </Card>
</CardGroup>