.env File Validator & Linter
.env File Validator: Checks trimmed non-comment lines for optional export, an ASCII key, an equals sign, and duplicate keys; it does not parse shell semantics.
About this .env file validator & linter
.env File Validator & Linter — browser-based utility.
How this tool works
Checks trimmed noncomment lines for optional export, an ASCII KEY name, and an equals sign, and reports duplicate keys. Values are otherwise accepted verbatim; quoting, interpolation, multiline values, and shell semantics are not parsed.
- Trim each line and skip blank or hash-prefixed lines.
- Match optional export plus an ASCII KEY=VALUE assignment.
- Report invalid lines and duplicate keys, or return the variable count.
Worked example
Scenario: Validate two ordinary dotenv assignments.
Sample input:
Processing: Trim lines, match the limited KEY=VALUE grammar, and count unique keys.
Illustrative output:
Limits and verification
It does not parse quoting, escapes, interpolation, multiline values, inline comments, shell expansion, required keys, value types, or secret safety.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
- Standard Browser Web API / Algorithm Implementation (No single external RFC/ISO standard)
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the .env File Validator & Linter workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
What dotenv syntax does the validator inspect?+
It trims each non-comment line, accepts an optional `export`, then requires an ASCII identifier followed by `=`. It reports malformed line numbers and duplicate keys while counting valid keys.
What does the two-variable example return?+
For `FOO=bar` and `COUNT=2`, the page returns `Valid dotenv file (2 variables).` This checks the documented assignment and count path; it does not load values into a shell.
Which dotenv rules are outside this checker?+
It does not interpret quotes, escapes, interpolation, multiline values, inherited environment, command substitution, permissions, or whether another dotenv loader accepts the file.
What does the browser test cover for dotenv input?+
The browser test enters dotenv text, runs the validator, and reads its page result. Its tool request log contains no request carrying that entered text; ordinary page resources, extensions, and wider browser traffic are separate.