Tutorial: Build a Todo App

Goal

Create a multiplatform todo flow with auth, database, and realtime updates.

Steps

1. Sign in user and save session
2. Load initial todo list from database.selectTyped<Todo>("todos")
3. Subscribe to INSERT and UPDATE events on todos
4. Upload attachment files (optional) to Storage
5. Invoke Edge Function for batch actions

Data model

@Serializable
data class Todo(
    val id: String,
    val title: String,
    val done: Boolean,
)

Success criteria

• New todos appear across clients in realtime
• Session survives app restart
• Error states are surfaced from SupabaseResult.Failure