ENV Validator

Usage examples

Case 1 · Valid .env

DATABASE_URL=postgres://localhost/app
JWT_SECRET=xxx
NODE_ENV=development

✓ All good. 3 keys valid.
  DATABASE_URL   — ok
  JWT_SECRET     — ok
  NODE_ENV       — ok

Case 2 · Missing & duplicate

DATABASE_URL=
API_KEY=123
API_KEY=456

⚠ line 1: Empty value for "DATABASE_URL"
⚠ line 3: Duplicate key "API_KEY"
✓ 1 key valid, 2 warnings

Case 3 · Syntax errors

1INVALID=foo
GOOD_KEY=ok
MALFORMED "broken

✗ line 1: Invalid key name "1INVALID"
✗ line 3: Missing "=" on line 3
✓ 1 valid, 2 errors

When to use this tool

→You're debugging a broken deploy and suspect a misconfigured .env

→You're onboarding a new teammate and want to verify their local .env before they start

→You're promoting config from staging to production and want a sanity check

→You need to validate CI/CD env injection produced a parseable file

→You're reviewing a PR that touches environment variables

Common mistakes

⚠Forgetting the = sign: APP_NAME My App is a syntax error; write APP_NAME="My App"

⚠Unterminated quotes: SECRET="abc silently swallows every key below it

⚠Invalid key name: 1FOO, API-KEY, and FOO BAR all fail — stick to [A-Z_][A-Z0-9_]*

⚠Declaring the same key twice: dotenv keeps the first, most other parsers keep the last

⚠Leaving a key empty when you meant to delete it: FOO= passes type checks but crashes at runtime

ENV Validator — Online .env Checker

The env validator is the fastest way to sanity-check a .env file before shipping. Paste your environment variables into the editor and the tool parses them client-side, highlighting every issue with line numbers so you can fix them in seconds.

Why .env files break things

Environment variables are loaded at runtime by most frameworks — Node.js, Next.js, Django, Rails, Laravel, Go, and others. A missing DATABASE_URL crashes the app. A duplicated API_KEY silently overrides. An unterminated quote corrupts every subsequent value. The validator catches all of these before you deploy.

Common issues we catch

Missing values — keys declared but never assigned.
Duplicate keys — the second value silently wins.
Invalid identifiers — keys starting with digits or containing dashes.
Unterminated quotes — values that swallow the rest of the file.
Whitespace and trailing commas — the little things that kill parsers.

Frequently asked

What does the .env validator check?

It parses your .env file and flags missing values, duplicate keys, invalid identifiers, unterminated quotes, and empty variables — the four most common causes of broken deploys.

Is my .env file uploaded anywhere?

No. The validator runs 100% in your browser. Your file never leaves your machine, and we don't log or store anything you paste.

Does it support export prefixes and quoted values?

Yes. Both `export KEY=value` and quoted values (single or double) are supported, matching the same syntax used by dotenv across Node, Python, and Ruby.

How is this different from a linter?

A linter runs in your editor. This is a quick, paste-and-check tool you can use in the browser when debugging a deploy — no config, no install.

What it does

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