JSON to .env Converter

Nested structures have to be flattened

Environment variables are a flat list of string pairs. A nested JSON object has no direct representation, so nesting must be flattened into compound keys, conventionally joined with underscores: a database object containing a host becomes DATABASE_HOST. Arrays are worse, becoming either indexed keys or a delimited string, and neither round-trips cleanly. If your configuration is deeply nested, environment variables may be the wrong destination for it.

Naming conventions matter

Convention is uppercase with underscores, and it is more than style: variable names are case-sensitive on Unix and case-insensitive on Windows, so mixed-case names behave differently across platforms. Names must not begin with a digit, and while many shells accept other characters, sticking to letters, digits and underscores avoids a class of quoting problems.

Quoting rules

Values containing spaces, a hash, or any shell metacharacter need quoting. A value with a hash left unquoted is truncated at that point by most parsers, which silently corrupts passwords and URLs containing a fragment. Values with newlines need double quotes and an escape sequence, and not every dotenv implementation supports multi-line values at all.

Everything becomes a string

JSON booleans and numbers lose their types: true becomes the four characters t-r-u-e, and the code reading it must interpret them. This trips people up because the string false is truthy in most languages, so a naive check on an environment variable set to false does the opposite of what was intended.

Handle the output like the secret it probably is

Configuration converted to .env usually contains credentials. The file belongs in .gitignore, should not be logged, and should not be pasted into a chat or ticket. Rotate anything that has been exposed rather than assuming nobody noticed.