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⚡️Lightning-fast linter for .env files. Written in Rust 🦀

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dotenv-linter can check / fix / compare .env files for problems that may cause the application to malfunction.

Available checks:

    ✅ Duplicated key
    ✅ Ending blank line
    ✅ Extra blank line
    ✅ Incorrect delimiter
    ✅ Key without value
    ✅ Leading character
    ✅ Lowercase key
    ✅ Quote character
    ✅ Space character
    ✅ Substitution key
    ✅ Trailing whitespace
    ✅ Unordered key
    ✅ Value without quotes

What is a .env file?

    💡 A .env file or dotenv file is a simple text file containing all the environment variables of a project.
    Storing configuration in the environment variables is one of the tenets of the Manifesto of Twelve-Factor App.
    The .env file has a simple key-value format, for example: FOO=BAR.
    More information you can find in articles in English and Russian.

The key features:

    ⚡️ Lightning-fast because it is written in Rust 🦀
    💣 Can be used on any project regardless of the programming language 💥
    🚀 Can be integrated with reviewdog and other CI services (including GitHub Actions and Super-Linter) 🔥

Articles about dotenv-linter:

👨‍💻 Installation

Pre-compiled binary

# Linux / macOS / Windows (MINGW and etc). Installs it into ./bin/ by default
$ curl -sSfL | sh -s

# Or a shorter way
$ curl -sSfL | sh -s

# Specify installation directory and version
$ curl -sSfL | sh -s -- -b usr/local/bin v2.0.0

# Alpine Linux (using wget)
$ wget -q -O - | sh -s

You can find other installation methods here:

🚀 Usage

✅ Check

By default, dotenv-linter checks all .env files in the current directory:

$ dotenv-linter
Checking .env
.env:2 DuplicatedKey: The FOO key is duplicated
.env:3 UnorderedKey: The BAR key should go before the FOO key

Checking .env.test
.env.test:1 LeadingCharacter: Invalid leading character detected

Found 3 problems

🛠 Fix

It can also fix the found warnings with the fix command:

$ dotenv-linter fix
Fixing .env
Original file was backed up to: ".env_1601378896"

.env:2 DuplicatedKey: The BAR key is duplicated
.env:3 LowercaseKey: The foo key should be in uppercase

All warnings are fixed. Total: 2

🤲 Compare

In addition, dotenv-linter can compare .env files with each other and output the difference between them:

$ dotenv-linter compare .env .env.example
Comparing .env
Comparing .env.example
.env is missing keys: BAR
.env.example is missing keys: FOO

Other use cases you can find on the documentation site (

🚦 Continuous Integration

dotenv-linter can also be used with CI services such as: GitHub Actions and Circle CI.

🚧 Benchmark

Benchmarking dotenv-linter/dotenv-linter and wemake-services/dotenv-linter has done using the hyperfine utility:

Command Mean [ms] Min [ms] Max [ms] Relative
dotenv-linter/dotenv-linter .env 2.7 ± 0.4 2.0 4.3 1.00
wemake-services/dotenv-linter .env 162.6 ± 12.1 153.0 201.3 60.83 ± 10.20
Content of .env file used for benchmarking


SECRET="my value"

SECRET=Already defined


✌️ Mentorship

dotenv-linter is not just a linter for .env files — it is also a contributor-friendly open-source project with the purpose of helping others learn Rust using a simple, but useful tool. 😊

In addition to studying Rust, this project has another goal — to promote love for open-source, help you with the first steps in it and give an opportunity to contribute to the open-source project written in Rust. ❤️

We act as a mentor within this project and help developers follow the path of a novice contributor from start to the top. 🤗

🤝 Contributing

If you've ever wanted to contribute to open source, now you have a great opportunity:

👍 Similar projects

✨ Contributors

This project exists thanks to all the people who contribute. [Contribute].

♥️ Sponsors

dotenv-linter is created & supported by Evrone. What else we develop with Rust.

Sponsored by Evrone

Become a financial contributor and help us sustain our community.

📃 License