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

# Apdex

> Learn how Apdex scoring works and how LoadForge helps you measure performance.

Apdex (**Application Performance Index**) is a standardized way to measure and interpret application response times based on user experience. It provides a simple numerical score representing **how satisfied users are with performance**.

## How Apdex Works

Apdex scores are based on response time thresholds:

* **Satisfied (Fast Response)**: Requests that complete within the target response time.
* **Tolerating (Acceptable Response)**: Requests that take longer but are still within an acceptable range (typically **4x the target response time**).
* **Frustrated (Slow Response)**: Requests that exceed the tolerable threshold, indicating poor performance.

The formula for **Apdex score**:

```plaintext theme={null}
Apdex = (Satisfied Requests + (Tolerating Requests / 2)) / Total Requests
```

* **1.0** = Excellent performance (all users satisfied)
* **0.85+** = Good performance
* **0.7 - 0.85** = Fair performance, potential for improvement
* **Below 0.7** = Poor performance, significant user frustration

## Apdex in LoadForge

LoadForge automatically calculates **Apdex scores** for every test and displays them in the **test results page**. This helps you quickly assess whether your site or API is performing as expected.

### Where to Find Your Apdex Score

* Every test run result in LoadForge includes an **Apdex calculation**.
* The Apdex score is displayed alongside **response time statistics (P95, average)** and **error rates**.
* If your Apdex score is **below your target**, LoadForge will **mark the test as failed**.

### Inside of a Run Result

<Frame caption="Apdex Report in Run Results">
  <img src="https://mintcdn.com/loadforge/-JPjrj7GdlQs4xIV/images/apdex-report.png?fit=max&auto=format&n=-JPjrj7GdlQs4xIV&q=85&s=e874330c5cded581b2af342c7fcd2fe6" alt="Apdex report" width="760" height="802" data-path="images/apdex-report.png" />
</Frame>

### On the List of Runs

<Frame caption="Apdex Scores in Runs List">
  <img src="https://mintcdn.com/loadforge/-JPjrj7GdlQs4xIV/images/apdex-table.png?fit=max&auto=format&n=-JPjrj7GdlQs4xIV&q=85&s=31020cf3485a244be2e166e427878bc4" alt="Apdex report" width="2317" height="414" data-path="images/apdex-table.png" />
</Frame>

## Setting Your Apdex Target

<Tip>Start with a more lenient Apdex target (higher ms) and gradually decrease it as you optimize your application. This creates achievable milestones for your team.</Tip>

When creating a test, you can define an **Apdex Target Response Time (in milliseconds)**. This is the response time under which requests are considered "satisfied."

### Recommended Apdex Targets

| Application Type        | Suggested Apdex Target |
| ----------------------- | ---------------------- |
| Static Websites         | **200ms - 500ms**      |
| APIs & Web Services     | **300ms - 800ms**      |
| E-Commerce Sites        | **500ms - 1000ms**     |
| Enterprise Applications | **1000ms - 2000ms**    |

## How to Improve Your Apdex Score

If your Apdex score is low, consider optimizing:

1. **Backend Performance**: Reduce database query times, optimize API calls.
2. **Caching**: Use caching layers (Redis, Cloudflare, etc.) to speed up response times.
3. **Scaling**: Increase server capacity or use auto-scaling for high-traffic periods.
4. **Content Optimization**: Minimize JavaScript execution, optimize images, and reduce page load times.
5. **CDN Usage**: Distribute static content across global locations to improve response times.

## Conclusion

Apdex provides an **objective measure of performance** that aligns with user experience. LoadForge integrates Apdex scoring **directly into test results**, making it easy to assess whether your application meets performance expectations.

By **setting realistic Apdex targets and monitoring test results**, you can continuously improve the responsiveness and reliability of your services.

<CardGroup cols={2}>
  <Card title="Run Results" icon="chart-bar" href="/runs/run-results">
    Learn how to interpret load test results and optimize performance
  </Card>

  <Card title="Comparing Runs" icon="code-compare" href="/runs/comparing-runs">
    Compare different test runs to track improvements over time
  </Card>
</CardGroup>