List to JSON Array Converter

Turn a plain list, one item per line, into a JSON array in a single click. This is the fastest way to move a column you copied from a spreadsheet, a text file or a chat message into code as a proper array. Each non empty line becomes one array element, surrounding whitespace is trimmed, and you can choose to keep every value as a string or auto detect numbers and booleans so that clean numeric lists become real numbers. Optional deduplication removes repeated lines while preserving the first occurrence order, which is handy for building lookup lists. Blank lines are ignored so stray newlines do not create empty entries. Paste your list, pick your options, click convert, and copy the array. Everything runs locally in your browser, so nothing you paste is sent to a server.