Origin Inserted RUM (OIR) vs. Edge Inserted RUM (EIR)

You can use the RUM JavaScript to gather and view the performance of Web pages served from your origin server prior to going live on the Edge Network. The RUM JavaScript collects performance data and sends it back to the Edge server. Metrics data collected in the browser include information such as page load time and first paint time, which can be seen in the RUM Time Series report.

In addition to viewing Web page performance at your origin, you also have the option of viewing Web page performance from the edge server. For details, see Enabling EIR.
Note: The impact of adding the RUM JavaScript to a Web page is minimal: it is a lightweight script that runs asynchronously.