Free ENV test files and sample generator

KEY=value environment variables (dotenv). Generate valid .env sample files for testing config loaders, secrets tooling and 12-factor apps.

Generate a .env file →

What is a .env file?

ENV: Environment Variables File. A .env file holds environment variables as KEY=value lines and is how most applications inject configuration in development. Because these files routinely hold secrets, tooling around them is worth testing carefully.

Why generate a test ENV file?

• Test a dotenv loader against many variables and comment lines.
• Verify secret-scanning or gitignore rules actually catch the file.
• Check precedence when values are also set in the real environment.

How a .env file is identified

A .env file has no signature at the start. A text format has no identifying leading bytes, so the extension and the reported media type are the only claims about it until a parser actually reads it, which is why validating uploads by extension alone is unsafe.

How the size lands on the exact byte

The format allows comments, so the padding is comment lines, legal, inert, and visible if you open the file.

Negative testing with broken ENV files

• Invalid. Identifiable, but wrong inside, so it fails during parsing.
• Corrupted. The leading bytes are destroyed. Same length as the valid file.
• Incomplete. Truncated part-way, so it is genuinely shorter.
• Empty. Chosen under Content rather than File Condition: valid structure, no data.

Which failure to reach for, and what to assert for each, is covered in how to make a corrupted file for testing. For upload limits and type checks see testing file upload validation, and for this format's encodings, UTF-16 and BOM test files.

Sample ENV content

VAR_0=137
VAR_1=274
VAR_2=411

This shows the shape of the file. Your download is generated fresh at the size you choose, so the values will differ.

How to open and verify the file

Any text editor; load with dotenv, or `set -a; . ./file.env; set +a` in a shell.

Media type text/plain · extension .env · category Config & DevOps

Generate a .env file → · questions about sizes, privacy or cost are answered on the site FAQ.

Frequently asked questions about ENV files

What identifies a .env file?

Nothing at the start of the file does. A text format has no identifying leading bytes, so the extension and the reported media type are the only claims about it until a parser actually reads it, which is why validating uploads by extension alone is unsafe.

How can a .env file be an exact number of bytes?

The format allows comments, so the padding is comment lines, legal, inert, and visible if you open the file.

Can I download several broken ENV files at once?

Yes, select more than one File Condition and you get one ZIP containing a .env per condition, each named after its condition.

Can the ENV file use UTF-16 or a byte-order mark?

Yes. .env is a text format, so it can be generated as UTF-8, UTF-8 with a byte-order mark, UTF-16 LE or UTF-16 BE. The body is shortened before re-encoding so the finished file still lands on the exact size you asked for. Note that a UTF-16 file always has an even byte count.

How do I open or verify the ENV file?

Any text editor; load with dotenv, or set -a; . ./file.env; set +a in a shell.

Related Config & DevOps formats

INI · TOML · Dockerfile · gitignore · CONF · Properties · Makefile · EditorConfig

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