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. 1

   Paste the .env-formatted text you want to validate into the input field.

2. 2

   Click the "Validate" button.

3. 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.