The .env File Format

godotenv supports a flexible format for .env files, closely matching the behavior of popular dotenv libraries in other languages. This page details the supported syntax.

Basic Key-Value Pairs

The core of the format is simple KEY=VALUE pairs.

KEY=VALUE
ANOTHER_KEY=some_other_value

Comments

Lines beginning with # are treated as comments and are ignored.

# This is a comment
DB_HOST=localhost # Comments at the end of a line are also supported

Whitespace

Whitespace around keys and unquoted values is trimmed.

# Both of these set the key 'KEY' to 'value'
  KEY = value
KEY=value 

Internal whitespace in unquoted values is preserved:

# Sets KEY to 'value one two'
KEY=value one two

Quoting

Values can be enclosed in single or double quotes, which is useful for values that contain whitespace or special characters.

Single Quotes (')

Values within single quotes are treated literally. No character escaping or variable expansion occurs.

SINGLE_QUOTED='This is a $LITERAL value with \n'
# SINGLE_QUOTED becomes 'This is a $LITERAL value with \n'

Double Quotes (")

Values within double quotes support variable expansion and escape sequences like \n (newline).

DOUBLE_QUOTED="Hello\nWorld"
# DOUBLE_QUOTED becomes "Hello" followed by a newline and then "World"

ESCAPED_QUOTE="This is an escaped \"quote\""
# ESCAPED_QUOTE becomes 'This is an escaped "quote"'

Multiline Values

Multiline values can be defined by including newlines directly within quoted strings.

PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----
... more key data here ...
-----END RSA PRIVATE KEY-----"

Variable Expansion (Substitution)

godotenv supports expanding variables within values. It replaces $VAR or ${VAR} with the value of that variable, looking first at other variables defined in the .env file and then in the host machine's environment.

# .env file
DOMAIN=example.com
EMAIL=user@${DOMAIN}

# From host environment (e.g., export HOME=/home/user)
APP_PATH=${HOME}/app

# Undefined variables are expanded to an empty string
UNDEFINED=${NON_EXISTENT_VAR}/path

Given the file above:

• EMAIL will be user@example.com.
• APP_PATH will be /home/user/app.
• UNDEFINED will be /path.

To use a literal $ sign, escape it with a backslash \$.

The export Prefix

The export keyword at the beginning of a line is supported for compatibility and is ignored during parsing.

export API_KEY=12345
# This is treated identically to API_KEY=12345

YAML-style Syntax

For convenience, a colon (:) can be used instead of an equals sign (=) as the separator, similar to YAML syntax.

# These are equivalent
API_KEY: 12345
API_KEY=12345