Environment Variables
Overview
We use different environment variables for different stages like developing, testing, and when the app is live.
This is done by using special files that have environments in them.
How the App Chooses the Right Environment Variables File
The app knows which file to use based on a special environment variable called APP_ENV.
If APP_ENV is set to staging, the app will use the variables from the staging file.
Development Stage
In this stage, we work on making the app and adding new things.
The app uses a file named .env.development which has special environment variables just for people who are building the app.
Testing Stage (Staging)
Here, we test the app to make sure it’s ready to go live.
We use the .env.staging file which has variables that help us test everything properly.
Live Stage (Production)
In the Production, the app is all done and people can use it.
App uses a file named .env.production which has environment variables for the app when it’s being used by everyone.
Environment Variables Schema Validation
We use Zod to check that our config is correct and in the right format. This is important to make sure the app works without any problems.
This setup is found in the src/config/index.ts file.
To prefix any variables intended for client-side exposure with NEXT_PUBLIC_.
When we add new environment variables to .env files, we need to make sure they match what we set up in the Zod schema.
Adding a New Variable
Here’s how to add a new environment variable to the application:
Identify the Environment Stages
Determine the environment stages where the new variable will be used.
Refer to the following table for file associations:
| APP_ENV | File |
|---|---|
| development | .env.development |
| staging | .env.staging |
| production | .env.production |
Update `.env` Files
Add the new variable to the respective .env files. For client-side variables, prefix them with NEXT_PUBLIC_.
NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY=pk_test_TYooMQauvdEDq54NiTphI7jx
Modify the Schema in `src/config/index.ts`
Update the schema in the config/index.ts file to include the new variable.
This step is crucial for schema validation.
const schema = z.object({
...
STRIPE_PUBLISHABLE_KEY: z.string(),
});
Update the Configuration Object
Add the new variable to the configuration object within the same file (config/index.ts), ensuring it matches the schema.
const processEnv = {
...
STRIPE_PUBLISHABLE_KEY: process.env.NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY,
};
All the environment variables we use in the front-end part of our app can be seen by everyone. So, don’t put any secret stuff like passwords or private keys there.
Keep those safe and only on the server side! 🛡️✨