It's a web UI tool you can use to **administrate users and rooms on your Matrix server**. It's designed to work with the Synapse homeserver implementation, but to some extent may work with [Dendrite](./configuring-playbook-dendrite.md) as well.
**Note**: Synapse Admin requires Synapse's [Admin APIs](https://matrix-org.github.io/synapse/latest/usage/administration/admin_api/index.html) to function. Access to them is restricted with a valid access token, so exposing them publicly should not be a real security concern. Still, for additional security, we normally leave them unexposed, following [official Synapse reverse-proxying recommendations](https://github.com/matrix-org/synapse/blob/master/docs/reverse_proxy.md#synapse-administration-endpoints). Because Synapse Admin needs these APIs to function, when installing Synapse Admin, the playbook **automatically** exposes the Synapse Admin API publicly for you. Depending on the homeserver implementation you're using (Synapse, Dendrite), this is equivalent to:
- for Synapse (our default homeserver implementation): `matrix_synapse_container_labels_client_synapse_admin_api_enabled: true`
- for [Dendrite](./configuring-playbook-dendrite.md): `matrix_dendrite_container_labels_client_synapse_admin_api_enabled: true`
### Sample configuration for running behind Caddy v2
Below is a sample configuration for using this playbook with a [Caddy](https://caddyserver.com/v2) 2.0 reverse proxy (non-default configuration where `matrix-nginx-proxy` is disabled - `matrix_nginx_proxy_enabled: false`).
```caddy
# This is a basic configuration that will function the same as the default nginx proxy - exposing the synapse-admin panel to matrix.YOURSERVER.com/synapse-admin/