.env Diff Tool

Most environment drift is invisible until a deploy breaks. Two .env files that look nearly identical can hide a changed database URL, a removed feature flag, or an added secret prefix — and eyeballing a couple of hundred lines of KEY=value is exactly how those differences slip past.

The .env Diff Tool compares two files by key name and reports only what matters: keys added in file B, keys removed from file A, and keys whose value changed, with both the old and new value shown. Ordinary unchanged keys stay out of the way, and a redaction toggle replaces values with [REDACTED] so the report can be shared without exposing secrets.

Matching is by key, not line order, so the output is a true semantic diff — deterministic, readable, and entirely computed in your browser.

• Key-based comparison: matches by name, ignores order and comments.
• Three categories: added, removed, and changed with old/new values.
• Unchanged grouping: identical keys are summarized, not listed.
• Redaction toggle: replace values with [REDACTED] for safe sharing.
• Clear output: markers (+ added / - removed / ~ changed) on every line.
• Corner-case safe: quoted values unwrapped, duplicates last-wins.
• Copy or download: clipboard or a .diff file in one click.
• Private: all conversion happens in your browser.

1. Paste file A (the reference) into the first box, or load the sample.
2. Paste file B (the comparison) into the second box.
3. Optionally enable redaction to mask value contents.
4. Click Compare. The diff report and summary appear on the right.
5. Review the categories — added, removed, changed — and share or save the report.

Example 1 — Staging vs production. An engineer diffs staging.env and production.env and instantly sees the three keys that differ in DATABASE_URL and feature flags.

Example 2 — Deploy review. A reviewer checks the diff between a PR's .env changes and main to confirm no secret was altered silently; the redaction toggle keeps the report shareable.

Example 3 — Local drift. A developer compares their local.env with the base to spot a DEBUG flag they forgot to turn off.

Example 4 — Compliance audit. An auditor compares environments quarterly; the report shows added and removed keys, proving nothing sensitive changed outside the approved set.

Example 5 — Onboarding comparison. A new hire diffs their generated local .env against the team sample and corrects the differences in minutes.

• Semantic diff: matches by key, not by line.
• Only the changes: unchanged keys stay out of the way.
• Safe to share: redaction hides value contents.
• Readable report: clear + - ~ markers and a summary.
• Deterministic: same files always produce the same diff.
• Private & free: browser-only, no account.