Add environment variables in create-react-app project

Create .env.example

Create a .env.example file that will serve as a template, providing defaults and placeholders. Check this file into Git. For example:

REACT_APP_API_URL=http://localhost:8080
REACT_APP_SENTRY_TOKEN=

Remember that create-react-app will only process env variables that begin with REACT_APP_ so make sure you include this prefix.

Create .env

Add .env to your .gitignore file. On local setup, each developer on your team can create a .env file using .env.example as a template.

REACT_APP_API_URL=http://localhost:8080
REACT_APP_SENTRY_TOKEN=abc123

Use env variables in JavaScript

console.log(process.env.REACT_APP_API_URL);

Use env variables in public/index.html

<title>%REACT_APP_SENTRY_TOKEN</title>