| Extension | XLSX |
| Full Name | Microsoft Excel Spreadsheet |
| Type | Document |
| Mime Type | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet |
| Format | Binary |
XLSX files have been around since the mid-2000's and are one of the most popular spreadsheet file formats available. It was created by Microsoft as a modern update to the existing Excel XLS file format, with the intention of making future improvements to the format easier to implement than the original XLS format.
Contained within an XLSX file is the spreadsheet data stored within XML files. The XLSX file itself is simply a compressed ZIP container, meaning the format allows for all the Excel assets, such as spreadsheet data, images, and charts, to be stored separately within a single file structure.
As well as being the native format used by Microsoft's Excel application, XLSX files can also be processed by other spreadsheet applications, and third-party conversion tools can easily interface with the XLSX file format.
| Extension | CSV |
| Full Name | Comma-separated Values |
| Type | Document |
| Mime Type | text/csv |
| Format | Text |
The CSV format is a very simple general data format that has been around for many years and allows any text-based data to be stored and exchanged between systems that can interpret CSV files with minimal development needed.
Data is stored within the file as a series of columns separated by a ',' character. The simplistic nature of CSV files has made them a popular choice for exchanging data between spreadsheet applications such as Microsoft's Excel and databases such as the many SQL-based databases.
Support for CSV files is widespread amongst spreadsheet and database software, making it possible to import and export CSV from Excel and other spreadsheets. SQL databases also offer options to exchange data between CSV files.
