text/csv

Spreadsheet interchange at its most deceptively simple. RFC 4180 pins down quoting and CRLF line endings, though real-world files honor neither. The charset question has a famous wrinkle: Excel assumes a legacy locale encoding unless the file opens with a UTF-8 byte-order mark, so exporters prepend EF BB BF even though a BOM is otherwise discouraged in UTF-8. Declare charset=utf-8 in the header, and keep the BOM if Excel users are downstream.

Defined by RFC 4180 · IANA registration. Registry facts from the IANA media-types registry via mime-db.