Env File Validator and Linter

A key must start with a letter or underscore and then contain only letters, digits and underscores, matching [A-Za-z_][A-Za-z0-9_]*. Names with hyphens, dots or spaces are flagged as errors because most dotenv loaders will not read them.

Errors are problems that usually break parsing, such as a line with no equals sign or an invalid key name, and they make the file report as not valid. Warnings are likely mistakes, such as duplicate keys or stray spaces, that many loaders tolerate but you probably did not intend.

Most dotenv parsers treat KEY=value literally, so KEY = value can store a key with a trailing space or a value with a leading space. The validator warns so you can remove the spaces and avoid surprises.

An unquoted value with spaces can be truncated or split by some loaders. Wrapping it in single or double quotes, like NAME="John Doe", keeps the whole value intact, so the tool suggests quoting it.

No. The file is parsed entirely in your browser, so its secrets never leave your device and nothing is sent to a server.