Check Missing Environment Variables Between Two .env Files
The nastiest configuration bug is the one that only exists in one environment: everything works locally, then production throws — or worse, silently falls back to a default — because one variable never made the trip. A missing-variable check takes seconds and prevents exactly that.
- ✓You added a variable locally three weeks ago and never told the staging or production file.
- ✓A teammate's 'works on my machine' turns out to be one undocumented key in their .env.
- ✓Auditing by eye fails past ~30 variables; files in real projects routinely carry 80+.
- ✓The checker lists missing keys by name (values stay masked), so you can fix the file without exposing secrets in a screenshot.
FAQ
What exactly does 'missing' mean here?
A key that exists in File A but has no entry at all in File B. A key present with an empty value counts as present, not missing — and shows up under Changed if A has a real value.
Should the check run in CI?
Ideally, yes — but when you are staring at two files right now, this page is the fastest way to get the answer. The JSON report export is designed to attach to that CI failure or PR.
Are my values uploaded for the check?
No. Parsing and comparison happen in your browser; the files never leave your device.