Missing Variable Checker

The Missing Variable Checker answers one question: does my .env still match the contract declared in .env.example? It scans both files, then reports every key the example expects that your real file is missing, empty, or hiding behind a comment.

Environment drift is invisible until deploy time. You add STRIPE_SECRET_KEY to a ticket, forget the .env entry, and the pipeline passes — tests on staging fail, and on Monday the report finally tells you. This tool makes that check instant and local, and it also flags orphan keys your .env carries that the example has since removed.

No uploads, no accounts, no logs. Paste both files and get a clear pass/fail list.

• Two-file comparison: .env against .env.example side by side.
• Missing keys: in example but not in .env.
• Empty-value flags: keys present but useless.
• Commented-out detection: required key hidden as #KEY=.
• Orphan keys: in .env but no longer in the example.
• Ignore-empty option: for deliberate empty switches.
• Summary verdict: clean, warnings, or failing.
• Private: all analysis is in-browser.

1. Paste your .env.example into the second box — this is the reference contract.
2. Paste your current .env into the first box, or load the sample.
3. Click Check. Missing keys are listed with their status.
4. Fix the gaps and re-run until the file is clean.

Example 1 — Fresh clone crash. A junior dev clones the repo, runs the app, and it dies on startup. The checker shows SESSION_SECRET is not in their .env at all — the .env.example contract was never copied.

Example 2 — Commented-out key. Someone disabled a feature by commenting out PAYMENTS_API_KEY=. The report flags the required key as commented-out so the shutdown is noticed, not silent.

Example 3 — Empty by mistake. An editor autosave wrote REDIS_URL= with an empty value. The checker marks it missing (empty).

Example 4 — Orphan cleanup. The example drops OLD_FEATURE_FLAG in a refactor; your .env still sets it. The report lists it as orphaned so maintenance can delete it.

Example 5 — CI gate. A pipeline runs this check and fails the build when required keys are missing before tests start.

• Catches drift early: before deploys, not after.
• Distinguishes states: absent, empty or commented.
• Report-only conflict: optional keys are listed, never forced.
• Contract aware: reads exactly what the example declares.
• Secret-safe: shows keys, and values only when empty.
• Free & local: no account, no upload.