Authorization for Realtime's Broadcast and Presence allows users to control access to channels using Row Level Security policies, enabling fine-grained authorization for sending and receiving messages, presence updates, and other operations within these channels. To implement this feature, users create RLS policies that define the permissions for a specific channel or topic, specifying whether a user can read, write, or perform other actions on the channel. Realtime checks these policies against the user's claims when they connect to a channel, ensuring that only authorized users can access and modify data within those channels. The approach is performance-oriented, caching policies in memory to minimize latency and maximizing throughput. This feature is currently available in Public Beta, with ongoing improvements and feedback encouraged from developers.