Initializing Supabase client - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Supabase Client Initialization Parameters

Which parameter is required to initialize a Supabase client correctly?

A The database username and password

B Only the Supabase URL

C Only the public anon key

D The Supabase URL and the public anon key

💡 Hint

Think about what the client needs to connect and authenticate.

The Supabase client requires both the URL to know where the service is and the anon key to authenticate requests.

❓ Configuration

intermediate

Correct JavaScript Code to Initialize Supabase Client

Which code snippet correctly initializes a Supabase client using the official JavaScript library?

A const supabase = new SupabaseClient('https://xyz.supabase.co', 'public-anon-key');

B

import { createClient } from '@supabase/supabase-js';
const supabase = createClient('https://xyz.supabase.co', 'public-anon-key');

C

import supabase from '@supabase/supabase-js';
const client = supabase('https://xyz.supabase.co', 'public-anon-key');

D const supabase = createClient('public-anon-key', 'https://xyz.supabase.co');

💡 Hint

Check the import statement and the order of parameters.

The official way is to import createClient and call it with the URL first, then the anon key.

❓ Architecture

advanced

Supabase Client Behavior in Server vs Client Environments

What is the main difference in Supabase client behavior when initialized in a server environment versus a client (browser) environment?

A In server environments, the client can use service role keys with full access; in client environments, only anon keys with limited access are used.

B In client environments, the client can access the database directly without keys; in server environments, keys are required.

C The Supabase client behaves identically in both environments with no difference in access control.

D In server environments, the client cannot connect to Supabase; only client environments can connect.

💡 Hint

Think about security and access control differences.

Server environments can safely use service role keys for full access, while client environments use anon keys with restricted permissions to protect data.

❓ security

advanced

Protecting Supabase Keys in Client Initialization

Which practice best protects your Supabase keys when initializing the client in a web application?

A Only expose the public anon key in client code; keep service role keys secret on the server.

B Use the same key for both client and server to simplify configuration.

C Embed the service role key directly in client JavaScript for faster access.

D Store all keys in the browser local storage for easy retrieval.

💡 Hint

Consider what keys should be public and which must remain secret.

The public anon key is safe to expose to clients; service role keys must remain secret on servers to prevent unauthorized access.

❓ service_behavior

expert

Supabase Client Behavior on Network Failure During Initialization

What happens if the Supabase client is initialized in a browser but the network is offline at that moment?

A The client initialization throws an error immediately and stops the app.

B The client caches all data locally and works fully offline without errors.

C The client initializes successfully but API calls will fail until network is restored.

D The client retries initialization automatically until the network is back.

💡 Hint

Think about initialization versus actual data requests.

Initializing the client just sets up configuration; it does not require network. API calls fail if offline, but initialization succeeds.