[Fixed] FirebaseError: Failed to load environment variables from .env – Firebase

The Solutions:

Solution 1: Reserved Firebase Names

The error is likely caused by using reserved Firebase names for environment variable keys. Reserved names start with the word "FIREBASE" and are used by Firebase to manage its internal settings. Using reserved names for custom environment variables can lead to conflicts and errors.

For example, if you have an environment variable named "FIREBASE_TEST", it may interfere with Firebase’s internal settings and cause the error. To resolve this issue, change the names of your environment variables to avoid using reserved names and ensure that they do not conflict with Firebase’s internal settings.

Solution 2: Check for Non-Uppercase ENV Keys

In addition to verifying the existence and syntax of the `.env` file, ensure that all environment keys are in uppercase. Dotenv files typically do not enforce this convention, but Firebase emulators may not tolerate lowercase keys. Check your `.env` file for any keys that deviate from this uppercase format and edit them accordingly.

Solution 3: Firebase reserved keys

Avoid using reserved keys in your `.env` file, such as “PORT.” These reserved keys are used by the Firebase Functions emulator and can cause conflicts.

Solution 4: Check the variables in .env file

Ensure that the .env file does not contain any reserved environment variables used by Firebase.
A list of reserved environment variables can be found at: https://firebase.google.com/docs/functions/config-env?gen=2nd#reserved-names

Video Explanation:

The following video, titled "Uncaught FirebaseError: Firebase: Error (auth/invalid-api-key ...", provides additional insights and in-depth exploration related to the topics discussed in this post.

Invalid API key - openweathermap.org error fixed ... Hiding API Key by Adding Custom Environment Variables | Complete React Course in Hindi #37.