A traditional chat application might require users to refresh the page to see new messages.
Realtime changes that experience.
Basic Structure
A chat application may have:
conversations
messages
members
Each message can contain:
id
conversation_id
sender_id
content
created_at
Sending a Message
The basic flow is:
User writes message
↓
Insert into PostgreSQL
↓
Realtime event
↓
Other participants receive update
Conversation Membership
Not every user should be able to read every conversation.
The database should associate users with conversations.
RLS
RLS can help ensure that a user can access only conversations they are authorized to access.
Message Ordering
Use a reliable timestamp or sequence mechanism when displaying messages.
Do not depend only on the order in which network requests arrive.
Attachments
If messages include files, store the files in Supabase Storage and keep their metadata with the message.
Scaling
As chat volume increases, monitor:
- Database workload
- Realtime connections
- Message volume
- Storage
- Query performance
Final Thoughts
Supabase combines PostgreSQL with Realtime capabilities, making it possible to build messaging backends without creating every realtime component from scratch.