Env File Validator

Overview

• Paste .env-formatted text (a list of KEY=VALUE lines) to check for syntax errors, duplicate keys, and unclosed quotes.
• Checks whether each line is in "KEY=VALUE" format, whether key names contain only letters, digits, and underscores, whether the same key is defined more than once, and whether quotes are properly closed.
• The text you enter is never sent anywhere — validation happens entirely in your browser.

Usage

1. Paste the .env-formatted text you want to validate into the input field.
2. Click the "Validate" button.
3. The line number and details of each issue found are listed. If there are no issues, "No issues found." is displayed.

Example

API_KEY=abc123
DEBUG=true
API_KEY=xyz789

Line 3: The key "API_KEY" is already defined on line 1 (duplicate).

Use Cases

• Checking for syntax mistakes or duplicate keys when reviewing a .env file created by someone else
• Checking that a file like .env.example is correctly formatted before wiring it into CI/CD
• Self-checking a manually edited .env file for mistakes before committing it

FAQ

Notes

• This tool only checks syntax and does not interpret dotenv-library-specific extensions such as variable expansion ($VAR or ${VAR}).
• Multi-line values are not supported. This tool targets the common .env format of one KEY=VALUE pair per line.
• "Duplicate key" is treated as a warning, while "not in KEY=VALUE format", "invalid key name", and "unclosed quote" are treated as errors.