EnvSync-LE: Zero Hassle .env Sync

Spot missing keys across your .env files before they bite
Automatic checks, a status bar counter, and a plain markdown report

Useful? A star or rating is how other developers find it — ★ GitHub · ★ Open VSX · ★ Marketplace

What it does

EnvSync-LE compares the variable names across the .env files in your workspace and tells you which files are missing which keys. It never reads or compares values, and it never modifies your files. Works in VS Code and in VS Code–based editors like Cursor and VSCodium (installable from Open VSX).

• Automatic checks — a debounced sync check runs whenever a watched .env file changes
• Status bar counter — the current issue count, one click away from the full report
• Markdown report — Show Details (Ctrl+Alt+S / Cmd+Alt+S) lists every missing key per file
• Three comparison modes — auto (union of all keys), manual (only the files you list), template (validate everything against one reference file; also reports keys a file has that the template lacks)
• Ignore list — temporarily exclude files (e.g. .env.example) from checking

Install

Use it from an AI agent

The same engine runs as an MCP server, so an agent can call it directly instead of you running a command.

compare_env_files(files[], mode?, templatePath?, caseSensitive?, maxResults?)

Takes file contents directly and reports which keys are missing from which file. Only key names are returned, never values — a dotenv file is where credentials live and the answer does not need them.

The server takes content and returns data — it reads no files and makes no network requests of its own. Published as envsync-le-mcp on npm and as io.github.nolindnaidoo/envsync-le in the MCP registry.

{
  "mcpServers": {
    "envsync-le": {
      "command": "npx",
      "args": ["-y", "envsync-le-mcp"]
    }
  }
}

npm install -g envsync-le-mcp

{
  "mcpServers": {
    "envsync-le": { "command": "envsync-le-mcp" }
  }
}

echo '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' | npx -y envsync-le-mcp

File classification

Classification is segment-based on the basename — app.device.env is not "development", and Windows paths classify correctly.

The CLI

The same comparison runs from a terminal or a CI step: a Rust CLI in crate/, sharing one corpus with the extension — crate/fixtures/ — so the two can never read a dotenv file differently.

envsync-le .                            # have these environments drifted?
envsync-le --template .env.example .    # will this deploy break?
envsync-le mcp                          # the same comparison over MCP on stdio

.env: missing STRIPE_KEY, SENTRY_DSN (in .env.example)
.env.production: missing SENTRY_DSN (in .env.example)
out of sync — 2 files with mismatches across 3 files

The exit code is the product — 0 in sync, 1 out of sync, 2 malformed question. Finding no dotenv files at all is 0: there is nothing to be out of sync with. Unlike the extractors in this family there is no list to pipe onward; the number is the answer.

It never reads a value. Only key names are parsed, compared or reported, and three separate checks enforce that rather than a promise.

Commands

Settings

Parsing notes

• Keys must match [A-Za-z_][A-Za-z0-9_-]*; anything else left of = is reported as a parse error for that line (the rest of the file still counts).
• export KEY=value is accepted; duplicate keys count once.
• Values quoted with ", ', or ` may span multiple lines; an unterminated quote is reported as an error.
• In auto mode the reference is the union of all keys, so "extra keys" only exist in template mode.

Languages

Twelve languages besides English:

German · Spanish · French · Indonesian · Italian · Japanese · Korean · Portuguese (Brazil) · Russian · Ukrainian · Vietnamese · Chinese (Simplified)