Environment variables and secrets in Supabase - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are environment variables?

Environment variables are like little notes your computer programs read to know important settings, such as passwords or API keys, without hardcoding them in the code.

beginner

Why should secrets not be hardcoded in your code?

Hardcoding secrets risks exposing them if the code is shared or leaked. Using environment variables keeps secrets safe and separate from the code.

intermediate

How does Supabase help manage environment variables and secrets?

Supabase lets you securely store environment variables and secrets in its dashboard, so your apps can access them safely without exposing sensitive data.

beginner

What is a common real-life example of environment variables?

Like a house key you keep safe and use only when needed, environment variables store keys or passwords your app uses to connect to services without showing them openly.

intermediate

What is the difference between environment variables and secrets?

Environment variables are any settings your app reads from outside the code. Secrets are a special kind of environment variable that hold sensitive info like passwords or tokens.

Why should you use environment variables for secrets?

A To keep sensitive data out of the code and secure

B To make the code run faster

C To store images and videos

D To replace database tables

Environment variables keep secrets safe by not embedding them directly in the code.

Where do you typically set environment variables in Supabase?

A In the Supabase dashboard under project settings

B Inside the app's main code file

C In the browser's console

D On your phone's settings

Supabase dashboard provides a secure place to set environment variables for your project.

Which of these is NOT a good practice for managing secrets?

A Using secret managers

B Using environment variables

C Hardcoding passwords in code

D Restricting access to secrets

Hardcoding passwords is unsafe and should be avoided.

What kind of information is stored as secrets?

A User interface colors

B Font styles

C Public blog posts

D API keys and passwords

Secrets include sensitive info like API keys and passwords.

How does using environment variables improve app security?

A By encrypting the entire app

B By separating sensitive data from code and controlling access

C By storing all data in the cloud

D By making the app load faster

Separating secrets from code helps prevent accidental leaks and controls who can see sensitive info.

Explain how environment variables and secrets work together in a Supabase project.

Think about how your app gets passwords without showing them in code.

Describe why it is important to keep secrets out of your code and how environment variables help.

Imagine sharing a photo without showing your house keys.

Practice

1. What is the main purpose of environment variables in Supabase?

easy

A. To display data on the website

B. To write SQL queries directly in the dashboard

C. To store important information like API keys outside the code

D. To create user accounts automatically

Solution

1. Step 1: Understand environment variables

   Environment variables hold data like API keys or URLs outside the code to keep it safe and flexible.

2. Step 2: Identify their use in Supabase

   Supabase uses environment variables to keep secrets safe and avoid hardcoding sensitive info.

3. Final Answer:

   To store important information like API keys outside the code -> Option C

4. Quick Check:

   Environment variables = store secrets safely [OK]

Hint: Environment variables keep secrets outside code [OK]

Common Mistakes:

• Thinking environment variables are for writing SQL
• Confusing environment variables with user data
• Assuming environment variables display data

2. Which is the correct way to reference an environment variable named SUPABASE_URL in a Supabase project?

easy

A. env.SUPABASE_URL()

B. process.env.SUPABASE_URL

C. getEnv('SUPABASE_URL')

D. SUPABASE_URL.value

Solution

1. Step 1: Recall environment variable syntax in JavaScript

   In JavaScript, environment variables are accessed using process.env.VARIABLE_NAME.

2. Step 2: Match with Supabase usage

   Supabase projects use this standard way to access environment variables like SUPABASE_URL.

3. Final Answer:

   process.env.SUPABASE_URL -> Option B

4. Quick Check:

   Access env vars with process.env.VAR [OK]

Hint: Use process.env.VAR to access environment variables [OK]

Common Mistakes:

• Using function calls like getEnv() which don't exist
• Trying to access variables as object properties incorrectly
• Forgetting the process.env prefix

3. Given this code snippet in a Supabase project:

const supabaseUrl = process.env.SUPABASE_URL;
const supabaseKey = process.env.SUPABASE_ANON_KEY;
console.log(supabaseUrl, supabaseKey);

What will be the output if SUPABASE_URL is set to https://xyz.supabase.co and SUPABASE_ANON_KEY is not set?

medium

A. https://xyz.supabase.co undefined

B. undefined undefined

C. https://xyz.supabase.co null

D. Error: SUPABASE_ANON_KEY not found

Solution

1. Step 1: Check environment variable values

   SUPABASE_URL is set to a URL string, but SUPABASE_ANON_KEY is missing, so it is undefined.

2. Step 2: Understand console.log output

   Logging both variables prints the URL string and undefined for the missing key.

3. Final Answer:

   https://xyz.supabase.co undefined -> Option A

4. Quick Check:

   Missing env vars print undefined [OK]

Hint: Missing env vars show as undefined in logs [OK]

Common Mistakes:

• Expecting an error when env var is missing
• Assuming missing vars print null
• Confusing undefined with empty string

4. You added a secret API_SECRET in the Supabase dashboard but your app still logs undefined when accessing process.env.API_SECRET. What is the most likely cause?

medium

A. You must include the secret in your code manually

B. The secret name is case-insensitive and should be lowercase

C. Supabase does not support environment variables

D. You forgot to restart the app after adding the secret

Solution

1. Step 1: Understand environment variable loading

   Environment variables are loaded when the app starts, so changes require a restart to take effect.

2. Step 2: Identify the cause of undefined

   If the app logs undefined, it likely did not reload the updated environment variables after adding the secret.

3. Final Answer:

   You forgot to restart the app after adding the secret -> Option D

4. Quick Check:

   Restart app to load new env vars [OK]

Hint: Restart app after adding secrets to load them [OK]

Common Mistakes:

• Thinking secret names are case-insensitive
• Believing Supabase doesn't support env vars
• Trying to hardcode secrets in code

5. You want to securely use a third-party API key in your Supabase Edge Function without exposing it in client code. Which approach is best?

hard

A. Store the API key as a secret in Supabase dashboard and access it via process.env inside the Edge Function

B. Hardcode the API key directly in the Edge Function code

C. Send the API key from the client app to the Edge Function on every request

D. Publish the API key in a public GitHub repo for easy access

Solution

1. Step 1: Understand secure storage of secrets

   Secrets like API keys should never be hardcoded or exposed publicly to avoid leaks.

2. Step 2: Use Supabase secrets in Edge Functions

   Storing the API key as a secret in the dashboard and accessing it via process.env inside the Edge Function keeps it secure and hidden from clients.

3. Final Answer:

   Store the API key as a secret in Supabase dashboard and access it via process.env inside the Edge Function -> Option A

4. Quick Check:

   Use secrets in server code, not client [OK]

Hint: Keep API keys in secrets, access only server-side [OK]

Common Mistakes:

• Hardcoding keys in code risking exposure
• Sending keys from client risking interception
• Publishing keys publicly causing leaks