Usage and limits
UTF-8 text/files: up to 1 MiB; data: 10,000 rows, 256 columns, 100,000 cells; output: 8 MiB. CSV values remain strings, without number or date inference. Header names must be nonempty and unique. JSON must be an array of flat objects or equal-width row arrays; duplicate keys and nested values are rejected. Large number and exponent tokens survive in CSV text, but null and missing values become blank cells. Formula protection is on by default and prefixes risky starts with an apostrophe, changing cell text. Import long ID columns as text in spreadsheets.