Apitally measures the time it takes your application to respond to API requests. On the performance dashboard, you can analyze response times and the Apdex score for your whole API and individual endpoints.

Response time distribution

The performance dashboard shows the 50th, 75th and 95th percentiles of API response times, helping you understand their distribution. For example, if the 95th percentile is high while the 50th and 75th percentile are low, it means that a small percentage of requests take a long time to complete.

When you click on an endpoint in the table, you can also see the response time distribution for that endpoint as a histogram.

Apdex score

The Apdex score is an open industry standard to measure user satisfaction with an application’s response times.

The score is based on a response time threshold (T) and four counts:

  • Satisfied: Response time is less than or equal to T.
  • Tolerating: Response time is greater than T but less than or equal to 4T.
  • Frustrated: Response time is greater than 4T.

The Apdex score is calculated as:

Apdex score=Satisfied+0.5Tolerating+0FrustratedTotal{\displaystyle\text{Apdex score} = \frac{\text{Satisfied} + 0.5 \cdot \text{Tolerating} + 0 \cdot \text{Frustrated}}{\text{Total}}}

Apdex scores range from 0 to 1, with 0 meaning that users were frustrated with all response times, and 1 meaning that users were satisfied with all response times.

Configuring the threshold

By default, Apitally assumes a response time threshold (T) of 500 ms. You can configure this threshold for your whole application and override it for individual endpoints.

To configure the threshold for your whole application, go to the Apps page, select Edit app in the dropdown for your application and change the “Response time threshold” field under Performance metrics.

To override the threshold for an individual endpoint, open the respective dropdown menu in the endpoints table on the performance dashboard, select Endpoint settings and update the “Response time threshold” field.