Standalone mode for RUM is available from version 2.x on.
Normally you would instrument your website with AEM RUM by adding the following script tag
<script defer type="text/javascript" src="https://rum.hlx.page/.rum/@adobe/helix-rum-js@^2/dist/rum-standalone.js"/>
You can pin a specific version number by using a URL like https://rum.hlx.page/.rum/@adobe/[email protected]/dist/rum-standalone.js instead.
If you use RUM in an standalone mode and you want to minimize the performance impact, you could route RUM requests via the same domain that serves your website. In this case, simply load the standalone script from the same domain and all RUM requests are routed through the same domain.
<script defer type="text/javascript" src="/.rum/@adobe/helix-rum-js@^2/dist/rum-standalone.js"/>
Please note, that the origin you set, must route /.rum/* requests to https://rum.hlx.page/.rum/*
For more complex setups, a different option is to set the global variable window.RUM_BASE before loading the script. All RUM requests will then use that domain.
E.g.
window.RUM_BASE = window.origin;