Your .env file is read in this tab only. It's never uploaded and never stored.
Why keep a .env.example
A .env file holds the settings and secrets an app needs, and it should never be committed. A .env.example lists the same keys with the values removed, so anyone setting up the project knows what to fill in. Keeping the comments from your own file explains what each value is for.
What is kept and what is removed
Every value is removed by default, including quoted and multi-line values such as private keys. Comment lines, comments after values, export prefixes and the blank lines that group settings are kept exactly as you wrote them; nothing is added. Lines that aren't KEY=value and repeated keys are left out and listed so you can fix the original.
Questions
Is it safe to paste real secrets here?
The page works entirely on your device and has no way to send what you paste anywhere. Even so, treat secrets with care: close the tab when you're done.
Can I keep some values?
Tick Keep harmless values to keep things like PORT=3000, DEBUG=false or NODE_ENV=development. Values whose key mentions a secret, token, password or key, values with a password inside a URL, and long random-looking strings are still removed.
Why is the download called env.example?
Browsers don’t save files whose names start with a dot, so the download is named env.example. Rename it to .env.example when you add it to your project, or use Copy and paste into a new file.
How do I check an old .env.example is up to date?
Open Compare with an existing .env.example and paste it. Keys in your .env that the example is missing, and keys the example has that your .env doesn't, are listed.