For non-React apps, we have a set of custom elements that you can embed in your web app.

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Initialization

If you have all the necessary information to initialize the SDK when the page renders (clientKey, userId, etc) you can initialize the SDK like this:

<body>
  <section>
    <h1>Hello World</h1>
    <courier-toast></courier-toast>
    <courier-inbox></courier-inbox>
  </section>
  <script type="text/javascript">
    window.courierConfig = {
      clientKey: "{{CLIENT_KEY}}",
      userId: "{{USER_ID}}",
    };
  </script>
  <!-- Be sure to use the appropriate version -->
  <script src="https://courier-components-xvdza5.s3.amazonaws.com/v{{CURRENT_VERSION}}.js"></script>
</body>

Github Docs: Courier Inbox JS SDK