Parse dotenv file content into key-value pairs

This parser turns complete .env file content into a clean object of key-value pairs while applying clear, predictable syntax rules. It ignores blank lines and comments, preserves quoted content, recognizes inline comments on unquoted assignments, and reports the exact line when an assignment is malformed. The result is useful for configuration previews, migration tools, validation steps, and developer utilities that need structured data without loading variables into a process environment.

Provide the complete dotenv text

Paste or submit the contents of a .env file in the text field. Each meaningful line must contain a key, an equals sign, and a value. Keys begin with an ASCII letter or underscore and may continue with letters, digits, or underscores. Blank lines are accepted, and any line whose first non-space character is a hash sign is treated as a comment. Empty assignments such as CACHE_PREFIX= are valid and produce an empty string. The parser returns a values object containing the parsed pairs plus a count of unique keys. If a key appears more than once, the later assignment replaces the earlier one, matching the practical override pattern commonly used when configuration fragments are combined. The parser never writes to the machine environment, expands variables, reads files, or contacts another service. It handles only the text supplied in the request, which makes its behavior safe to preview and straightforward to reproduce in a build script, editor extension, configuration checker, or migration workflow.

Understand quotes, escapes, and comments

Unquoted values have surrounding whitespace removed. A hash sign begins an inline comment only when whitespace appears immediately before it, so URL fragments and tokens such as color=#fff remain intact. Single-quoted values preserve their inner text literally, including hash signs and spaces. Double-quoted values also preserve spaces and hash signs, while interpreting familiar backslash escapes for newline, carriage return, tab, a double quote, and a backslash. After a closing quote, only whitespace or a comment is allowed. These rules remove ambiguity without attempting shell evaluation. The parser does not interpolate references such as ${HOST}, execute command substitutions, or convert strings like true and 8080 into booleans or numbers. Every parsed value remains a string, because dotenv data is textual and callers should decide how application-specific coercion works. This distinction matters when leading zeroes, case, or an intentionally empty value carries meaning that automatic conversion could accidentally destroy.

Handle invalid input deliberately

A nonblank, noncomment line without an equals sign is rejected rather than silently skipped. The same applies to an invalid key, a quoted value without a closing quote, or unexpected characters after a closing quote. Error messages include the one-based line number so a person or automated editor can locate the problem quickly. This strict failure behavior is especially useful before deployment: accepting half of a damaged configuration file can hide a missing setting until an application starts with surprising defaults. Submit the parser result only after the request succeeds, and treat an invalid-input response as a reason to repair the source text. Because parsing is deterministic, the same content always produces the same object and the same malformed line always produces the same error. API requests cost $0.002; the browser runner uses the same pure parsing logic, making it convenient to test syntax interactively before adding the operation to an automated configuration pipeline.