ENV File Validator

Validate your .env files for duplicate keys, empty values, missing quotes, invalid characters, and syntax errors. Get line-by-line diagnostics with a cleaned output. 100% client-side.

About .env File Validation

The .env file is a common pattern for storing environment-specific configuration. This validator checks for common mistakes that can cause hard-to-debug issues in your application.

What We Check

  • Duplicate keys: Same variable defined multiple times (last value wins, which is often unintended)
  • Empty values: Keys with no value assigned (might cause runtime errors)
  • Invalid key names: Keys must be alphanumeric with underscores, cannot start with a number
  • Unmatched quotes: Strings with opening quotes but no closing quotes
  • Spaces in unquoted values: Values with spaces that should be quoted
  • Lines without =: Invalid syntax (not a comment, not blank, no assignment)
  • Trailing whitespace: Invisible characters that can cause value mismatches
  • Inline comments: Comments after values may be included in the value depending on the parser

Best Practices

  • Always quote values containing spaces, #, or special characters
  • Use UPPER_SNAKE_CASE for key names
  • Never commit .env to version control
  • Provide a .env.example with placeholder values

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