# Build-time environment variables As siibra-explorer uses [webpack define plugin](https://webpack.js.org/plugins/define-plugin/), where necessary, the environmental variables are `JSON.stringify`'ed and directly replaced in the code. | name | description | default | example | | --- | --- | --- | --- | | `PRODUCTION` | if the build is for production, toggles optimisations such as minification | `undefined` | true | | `BACKEND_URL` | backend that the viewer calls to fetch available template spaces, parcellations, plugins, datasets | `null` | https://interactive-viewer.apps.hbp.eu/ | | ~~`BS_REST_URL`~~ _deprecated. use `SIIBRA_API_ENDPOINTS` instead_ | [siibra-api](https://github.com/FZJ-INM1-BDA/siibra-api) used to fetch different resources | `https://siibra-api-stable.apps.hbp.eu/v1_0` | | `SIIBRA_API_ENDPOINTS` | Comma separated endpoints of [siibra-api](https://github.com/FZJ-INM1-BDA/siibra-api) used to fetch different resources | `https://siibra-api-stable.apps.hbp.eu/v2_0,https://siibra-api-stable-ns.apps.hbp.eu/v2_0,https://siibra-api-stable.apps.jsc.hbp.eu/v2_0` | | `MATOMO_URL` | base url for matomo analytics | `null` | https://example.com/matomo/ | | `MATOMO_ID` | application id for matomo analytics | `null` | 6 | | `STRICT_LOCAL` | hides **Explore** and **Download** buttons. Useful for offline demo's | `false` | `true` | | `KIOSK_MODE` | after 5 minutes of inactivity, shows overlay inviting users to interact | `false` | `true` | | `EXPERIMENTAL_FEATURE_FLAG` | enabling experimental features | `false` | `true` | | `ENABLE_LEAP_MOTION` | enable leap motion controller | `false` | `true` |