}
```
+#### API_HOST
+
+The Arvados base URL.
+
+The `REACT_APP_ARVADOS_API_HOST` environment variable can be used to set the default URL if the run time configuration is unreachable.
+
#### VOCABULARY_URL
Local path, or any URL that allows cross-origin requests. See
[Vocabulary JSON file example](public/vocabulary-example.json).
+To use the URL defined in the Arvados cluster configuration, remove the entire `VOCABULARY_URL` entry from the runtime configuration. Found in `/config.json` by default.
+
### FILE_VIEWERS_CONFIG_URL
Local path, or any URL that allows cross-origin requests. See:
[File viewers config scheme](src/models/file-viewers-config.ts)
+To use the URL defined in the Arvados cluster configuration, remove the entire `FILE_VIEWERS_CONFIG_URL` entry from the runtime configuration. Found in `/config.json` by default.
+
### Licensing
Arvados is Free Software. See COPYING for information about Arvados Free