React Load Different .env For Local, Dev, And Prod

Introduction to React: The importance of environment variables and the .env file

React is a popular JavaScript library used for developing web applications. One of the important aspects of building React applications is setting up the environment variables and the .env file.

Environment variables are used to store sensitive information such as API keys, database credentials, and other configuration parameters. The .env file is a configuration file that allows developers to manage and access these variables throughout the application.

In a React application, environment variables are used to manage different settings for different environments such as local, development, and production. This helps in preventing the leakage of sensitive information and improves security while also making it easier to manage different settings for different environments.

Setting up a local development environment for React: Understanding the different .env files and their usage

When developing a React application, it is important to have a local development environment that allows you to test and debug your code before deploying it to production. One crucial aspect of setting up a local development environment for React is understanding the different .env files and their usage.

The .env files are configuration files that contain environment variables that your React application needs to run. These files are named based on the environment they are intended for, such as .env.local for local development, .env.development for development, and .env.production for production.

The purpose of having different .env files for different environments is to maintain separation of concerns and prevent sensitive information from being exposed to the wrong audience. For example, your local development environment may require different API keys than your production environment. By separating the variables into different .env files, you can ensure that only the necessary variables are exposed to each environment.

When your React application runs, it looks for a .env file specific to the current environment and loads the environment variables from it. In a local development environment, it will look for .env.local and load the variables from there. In a development environment, it will look for .env.development and in a production environment, it will look for .env.production.

Understanding and properly setting up the different .env files for your React application can save a lot of time and headaches when it comes to debugging and deploying your code. Take the time to familiarize yourself with this aspect of React development, and you will be well on your way to building robust and scalable applications.

How to load different .env files for different environments (dev, prod) in React

When working on a React project, you might need to use different environmental variables based on the environment you are working in. For example, you might want to connect to a different API endpoint for development and production.

One way to handle this is to use separate .env files. Here’s how you can load different .env files for different environments in React:

  1. Create separate .env files for each environment (e.g. .env.local for local development, .env.development for development, .env.production for production).
  2. Add the necessary environmental variables to each file. For example:
  3. REACT_APP_API_URL=http://localhost:3000/api

  4. In your React project, install the dotenv package:
  5. npm install dotenv

  6. In your entry file (usually index.js), add the following code at the top:
  7. require('dotenv').config({ path: `.env.${process.env.NODE_ENV}` })

  8. When you run your project, set the NODE_ENV environment variable to the appropriate value (e.g. “local”, “development”, “production”).

With these steps, you can easily switch between different environments and load different environmental variables as needed in your React project.

Understanding the role of NODE_ENV in configuring React environments

In a React project, different environments utilize different configurations. You may have noticed files named .env.local, .env.development, .env.test, and .env.production in your project directory. These files contain environment-specific variables that can be accessed during runtime using the Node.js environment variable, NODE_ENV.

NODE_ENV is a crucial parameter in deciding which environment-specific file to use and which configuration to apply. The value of NODE_ENV can be set to “development,” “test,” or “production” depending on the environment you want to configure. These values tell React which file to read and, as a result, which configuration to use.

For instance, if NODE_ENV is set to “development,” the .env.development file will be read, and its variables will be loaded. Similarly, if NODE_ENV is set to “production,” React will read the .env.production file and apply the configuration specified, such as minifying code, disabling developer-specific features, etc.

It is essential to understand the role of NODE_ENV and its impact on your project’s configuration, especially when working on large projects with multiple environments. Proper configuration based on the environment can save you time, avoid errors, and enhance your project quality.

Advanced configuration: Customizing .env files for different React components and modules

When working with React, it’s not uncommon to have different components and modules that require access to different environment variables. In these scenarios, it can be helpful to customize your .env files for each component or module to keep your code organized and prevent potential conflicts.

Thankfully, React provides an easy way to load different .env files based on your current environment (local, dev, prod, etc.). To do this, you can use a package like dotenv to load the appropriate .env file for your current environment variables.

Once you have dotenv installed, you can create different .env files for each component or module, and use the dotenv package to load the appropriate file based on your environment. This can be especially helpful when working with APIs or other external services that require different environment variables for each component or module.

Overall, customizing .env files for different React components and modules is a great way to keep your code organized and prevent potential conflicts. With the help of packages like dotenv, you can easily load the appropriate environment variables for each component or module, making your code more efficient and easier to manage.


When it comes to building React projects, managing environment variables can be challenging, especially when dealing with multiple environments such as local, development, and production. In this blog post, we will discuss the best practices for managing multiple .env files in React projects.

Create specific .env files for each environment

The first step to managing multiple .env files is to create specific files for each environment. For example, you can create a .env.local file for your local development, .env.development file for your development environment, and .env.production file for your production environment. This approach will enable you to set environment-specific variables and avoid conflicts.

Use GitIgnore file to exclude sensitive data

Since .env files contain sensitive data such as API keys and passwords, it’s crucial to exclude them from version control. Using a GitIgnore file to exclude these files will ensure that your sensitive data does not get pushed to your repository accidentally.

Define default values for all variables

To ensure that your application runs smoothly, you should define default values for all environment variables. This practice is particularly vital when dealing with variables that are not environment-specific. Defining default values for your variables will ensure that your application runs even when some variables are not set.

Use environment variables in your React application

After defining your environment variables, you can use the ‘process.env.‘ to access the variables in your application. For example, if you set ‘REACT_APP_API_KEY’ in your .env file, you can access it in your application using ‘process.env.REACT_APP_API_KEY.’


Managing multiple .env files in a React project can be overwhelming. However, using the best practices we have discussed above will enable you to manage your environment variables effectively, thereby improving the development and deployment processes of your application.

Troubleshooting Common Issues with .env File Configuration in React

If you are working on a React project that requires environment-specific configuration, such as API endpoints or credentials, then you may be using a .env file to store this information. While this approach can be effective, it is not without its challenges and you may run into some common issues when configuring your .env file.

1. Ensure Correct File Naming and Placement

First and foremost, it is important to ensure that your .env file is named correctly and placed in the right directory. In general, the file should be called “.env” and located at the root directory of your React project. However, if you are using different configurations for local, development, and production, then you may need to rename your files accordingly (e.g. “.env.local”, “.env.development”, and “.env.production”) and place them in the respective directories.

2. Use the Correct Prefix

By default, React expects all environment variables to start with “REACT_APP_”. This prefix is used to ensure that only whitelisted environment variables are available, as a security measure. Therefore, it is important to ensure that any environment variables you define in your .env file follow this convention.

3. Check for Typos and Syntax Errors

If your environment variables are not working as expected, then you may have typos or syntax errors in your .env file. Double-check to ensure that all variables are spelled correctly and that the syntax is correct. This includes ensuring that all values are enclosed in quotes, where necessary.

4. Restart Your Development Server

Sometimes, changes to your .env file may not be picked up by your development server until it is restarted. Therefore, if you have made any changes to your .env file, it is important to stop and restart your development server to ensure that the changes take effect.

By keeping these common issues in mind and following best practices for .env file configuration in React, you can avoid many of the pitfalls that can arise when working with environment-specific configuration in your projects.

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