Projects often rely on environmental variables stored in a .env file to run... and because these variables sometimes contain sensitive data, we never add them to source control. Instead, these variables are added e.g. to a .env.example file so it's easy to get the project running for other developers. However, it's very easy to forget to update this file when a variable is added/updated in .env (during development). This can make it difficult for devs to get the project running (locally) because they rely on .env.example file to setup their environment (with their own configs). sync-dotenv automates the process of keeping your .env in sync with .env.example.