# Registering an Application Service The registration of new application services depends on the homeserver used. In synapse, you need to create a new configuration file for your AS and add it to the list specified under the `app_service_config_files` config option in your synapse config. For example: ```yaml app_service_config_files: - /home/matrix/.synapse/<your-AS>.yaml ``` The format of the AS configuration file is as follows: ```yaml url: <base url of AS> as_token: <token AS will add to requests to HS> hs_token: <token HS will add to requests to AS> sender_localpart: <localpart of AS user> namespaces: users: # List of users we're interested in - exclusive: <bool> regex: <regex> group_id: <group> - ... aliases: [] # List of aliases we're interested in rooms: [] # List of room ids we're interested in ``` `exclusive`: If enabled, only this application service is allowed to register users in its namespace(s). `group_id`: All users of this application service are dynamically joined to this group. This is useful for e.g user organisation or flairs. See the [spec](https://matrix.org/docs/spec/application_service/unstable.html) for further details on how application services work.