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 · ★ Marketplace · ★ Open VSX

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

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.

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)

Both halves are covered — the manifest (command titles, setting names and descriptions) and everything shown while the extension runs (notifications, the status bar, quick-picks and prompts). The extension follows VS Code's display language, so it matches whatever the editor is already set to; no setting of its own.

Privacy & security

• No network access. The extension never sends data anywhere. The telemetryEnabled setting only writes events to a local Output Channel you can inspect (envsync-le).
• Values are never read, displayed, or logged — only key names are compared.
• The MCP server returns key names, never values. A dotenv file is where credentials live, so the server reports which keys are missing or extra and nothing about what they contain. It takes file contents as an argument rather than paths, so it reads no files and makes no network calls; the bundle gate asserts a known value is absent from its response.
• Error notifications redact home directories and credential-shaped fragments.

Development

bun install
bun run build            # esbuild bundle -> dist/extension.js
bun run typecheck        # tsc --noEmit (includes tests)
bun run test             # vitest unit suite
bun run test:integration # real VS Code extension host
bun run lint             # biome
bun run package          # VSIX into release/

Architecture and conventions live in AGENTS.md. Changes are tracked in CHANGELOG.md.

Performance

Median of 7 runs after warmup, on Apple M5 Pro, 24 GB RAM, Node 24.3.0. Inputs are generated by scripts/benchmark.ts rather than checked in, so the sizes above are exactly what was measured. Reproduce with bun run benchmark.

These are machine-specific and are not asserted in CI — a benchmark that gates a build only tells you how busy the runner was.

Testing

172 test cases across 13 files, plus an integration suite that runs in a real VS Code extension host and an end-to-end test that installs the built .vsix into a clean profile.

Generated from coverage/coverage-summary.json by scripts/coverage-readme.js; CI fails if this section drifts from a fresh run. Reproduce with bun run test:coverage.

More from the LE Family

Every tool in the family, one page: letools.dev

All ten also ship as MCP servers — npx <name>-mcp gives any agent the same engine.

• String-LE - Extract string values for i18n from JSON, YAML, CSV, TOML, INI, and .env
• Numbers-LE - Extract numeric values from JSON, YAML, CSV, TOML, INI, and .env
• Paths-LE - Extract file paths from JS/TS imports, JSON, HTML, CSS, TOML, CSV, and .env
• Regex-LE - Find, test, and validate regular expressions with ReDoS screening
• Secrets-LE - Detect and sanitize credentials locally, before you commit
• Scrape-LE - Check whether a page is scrapeable before you write the scraper
• Colors-LE - Extract and analyze colors from CSS, SCSS, LESS, Stylus, HTML, JS/TS, and SVG
• URLs-LE - Extract URLs from documentation, configs, and code
• Dates-LE - Extract and analyze dates from logs, configs, and code

Also by nolindnaidoo

Rust

• pixelcoords — Freeze your screen, mark regions, get pixel-exact coordinates and crops pixelcoords.dev · crates.io · docs.rs
• pixelactions — Consume human-verified coordinates, perform the interaction, confirm it landed pixelactions.dev · crates.io · docs.rs

Contact Developer — GitHub · LinkedIn

License

MIT © nolindnaidoo