A single-file, in-browser tool to diff and merge two .env files. Paste both files, pick a base, and decide what happens to changed values, new keys, and removed keys. Everything runs client-side, nothing leaves the page.
Open index.html in a browser, paste your two env files, and copy the merged result.
The output keeps the base file's layout: comments, blank lines, and key order are preserved, and only the value part of a line is swapped when the other file wins.
A typical use case: cleaning up a .env backup (in a password manager, for example) against the live file. Start from the backup, update stale values from live, add keys that are new on live, and remove keys that no longer exist.