.env Parser & Validator
About .env Parser / Validator
.env Parser / Validator checks environment files before they reach a shell, application framework or deployment platform, while keeping secret values out of diagnostics.
How it works
Practical dotenv syntax
The parser supports comments, export prefixes, unquoted values, single and double quotes, escapes and multiline quoted values. Invalid names, missing equals signs and malformed quote endings are located by line.
Duplicate and empty checks
Every definition is inventoried so repeated variables and empty assignments can be rejected instead of silently inheriting runtime-specific last-one-wins behavior.
Reference warnings
Optional interpolation linting finds ${NAME} references with no definition in the same file. Reports include variable names and locations, never their values.
Frequently asked questions
Is there one official .env specification?
No. Dotenv consumers differ. This parser targets the widely shared KEY=VALUE conventions and reports ambiguous cases rather than expanding variables.
Are ${VAR} expressions expanded?
No. They are preserved as text and only checked for missing in-file definitions when warnings are enabled.
Can validation leak a secret in the report?
Diagnostics contain variable names and line numbers only; parsed values are not copied into the report.
Sources & last verified
The behaviour of this tool and the claims on this page were checked against the specifications below on . Everything runs in your browser, so the output you see is exactly what the engine produced.
Found a wrong result or an outdated claim? Report an error and it will be re-verified.