The following requirements applies to any frontend implementation:

• A frontend MAY do mostly whatever it wants to, including creating threads, opening TCP ports and exposing Mopidy for a group of clients.
• A frontend MUST implement at least one Pykka actor, called the "main actor" from here on.
• The main actor MUST accept two constructor arguments:
  • config, which is a dict structure with the entire Mopidy configuration.
  • core, which will be an :class:`ActorProxy <pykka.proxy.ActorProxy>` for the core actor. This object gives access to the full :ref:`core-api`.
• It MAY use additional actors to implement whatever it does, and using actors in frontend implementations is encouraged.
• The frontend is enabled if the extension it is part of is enabled. See :ref:`extensiondev` for more information.
• The main actor MUST be able to start and stop the frontend when the main actor is started and stopped.
• The frontend MAY require additional config values to be set for it to work.
• Such config values MUST be documented.
• The main actor MUST raise the :exc:`mopidy.exceptions.FrontendError` with a descriptive error message if the defined config values are not adequate for the frontend to work properly.
• Any actor which is part of the frontend MAY implement the :class:`mopidy.core.CoreListener` interface to receive notification of the specified events.

See :ref:`ext-frontends`.