Quick start

1. Install

npm install --save-dev envvet
# or: pnpm add -D envvet  ·  yarn add -D envvet

You can also run it without installing via npx envvet.

2. Commit a contract

envvet checks your real .env against an .env.example — the contract that lists every variable the app needs. If you don’t have one yet, create it next to your .env and commit it:

# .env.example  (committed)
API_KEY=
LOG_LEVEL=

Leave the values blank — the example documents the keys, not the secrets. Your .env stays gitignored.

3. Run it

From the project root, with no arguments:

npx envvet

envvet auto-detects .env and .env.example in the current directory, compares them, prints a report, and exits non-zero if anything has drifted.

Missing (1)
  • LOG_LEVEL

Empty (1)
  • API_KEY

Extra (1)
  • EXTRA_THING

4. Read the report

Each section maps to a kind of drift:

Missing — the example expects the key, your .env doesn’t set it. Add it.
Empty — the key is present but its value is blank. Fill it in.
Extra — your .env has a key the example doesn’t list. Add it to the example, or pass --allow-extra if it’s intentionally local.

Fix the drift and run again until you get the clean line and an exit code of 0:

All environment variables present.

5. Gate your PRs

Drop a step into your pipeline so a drifted contract fails the build. Since .env is usually gitignored, check the example against itself (or against an .env you materialise from secrets — see CI):

name: env
on: [push, pull_request]
jobs:
  envvet:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npx envvet --env .env.example --example .env.example

That’s it — a non-zero exit fails the job with no extra wiring. See the CLI reference for every flag and exit code.