Supabase architecture (Postgres, Auth, Storage, Realtime, Edge Functions) - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Supabase Auth Behavior

Which of the following best describes how Supabase Auth manages user sessions after login?

A Supabase Auth stores the session token only in memory and loses it on page reload.

B Supabase Auth stores a session token in local storage and automatically refreshes it using a refresh token.

C Supabase Auth requires the user to manually re-login every 30 minutes to maintain session.

D Supabase Auth uses cookies that expire immediately after login, requiring constant re-authentication.

💡 Hint

Think about how persistent login works in web apps.

Supabase Auth securely stores session tokens in local storage and uses refresh tokens to keep the session alive without user intervention.

❓ Architecture

intermediate

Supabase Storage Usage Scenario

You want to store user-uploaded images in Supabase Storage. Which statement correctly describes how Supabase Storage integrates with other Supabase services?

A Supabase Storage requires manual configuration of access rules outside of Supabase Auth.

B Supabase Storage is a separate service and does not integrate with Supabase Auth for access control.

C Supabase Storage automatically replicates files into the Postgres database for backup.

D Supabase Storage uses Supabase Auth to control access to files, allowing only authenticated users to upload or download files.

💡 Hint

Consider how access control is unified in Supabase.

Supabase Storage integrates with Supabase Auth to enforce access control, ensuring only authorized users can manage files.

❓ service_behavior

advanced

Realtime Updates with Supabase Realtime

Given a Supabase Realtime subscription to a Postgres table, what happens when a new row is inserted into that table?

A The client subscribed to the table immediately receives a realtime event with the new row data.

B Supabase Realtime only sends events for updates, not inserts.

C The new row is only visible after a manual refresh of the client application.

D The client must poll the database every few seconds to see new rows.

💡 Hint

Realtime means instant updates pushed to clients.

Supabase Realtime listens to Postgres changes and pushes insert, update, and delete events instantly to subscribed clients.

❓ Configuration

advanced

Edge Functions Deployment in Supabase

Which of the following is true about deploying Edge Functions in Supabase?

A Edge Functions are serverless functions deployed close to users for low latency and scale automatically.

B Edge Functions run on the client device and require manual scaling.

C Edge Functions must be deployed inside the Postgres database as stored procedures.

D Edge Functions only run during database migrations.

💡 Hint

Think about what 'edge' means in cloud computing.

Supabase Edge Functions are serverless, run near users geographically, and scale automatically without manual intervention.

❓ security

expert

Securing Supabase Postgres with Row Level Security (RLS)

You want to ensure users can only see their own data in a Supabase Postgres table. Which RLS policy correctly enforces this?

Supabase

CREATE POLICY "Users can view their own data" ON messages FOR SELECT USING (auth.uid() = user_id);

A The policy allows users to select rows where the Postgres user ID matches the user_id column.

B The policy allows all users to select all rows without restriction.

C The policy allows users to select rows where the Supabase auth.uid() matches the user_id column.

D The policy denies all SELECT operations on the messages table.

💡 Hint

auth.uid() returns the current logged-in user's ID.

This RLS policy uses Supabase's auth.uid() function to compare with the user_id column, restricting access to only the user's own rows.