airbyte/airbyte-webapp/docs/HowTo-EnvVariables.md

Environment variables

Currently we have 2 types of environment variables:

1. Statically injected build time variables
2. Dynamic env variables injected via window

Static env variables

The environment variables are embedded during the build time. Since our app is based on Create React App that produces a static HTML/CSS/JS bundle, it can’t possibly read them at runtime.

Static env variables name should always start with REACT_APP_

Dynamic env variables

Dynamic env variables in our cases are injected into app by nginx

<script language="javascript" \>
  window.TRACKING_STRATEGY = "$TRACKING_STRATEGY";
  window.AIRBYTE_VERSION = "$AIRBYTE_VERSION";
  window.API_URL = "$API_URL";
</script>
;

later we can use any of the declared variables from window