| 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 | TXT |
| Full Name | Plain Text File |
| Type | Document |
| Mime Type | text/plain |
| Format | Text |
A TXT file is a simple text file that contains only plain text characters; binary data cannot be stored in text files. Text files allow storage of simple text documents where rich text formatting features such as bold, italic, underline, etc. are not needed.
Initially, text files could only store characters residing in the ASCII character set; however, over the years, character encoding properties have been added to allow for non-ASCII characters to be represented using formats such as UTF8 and UTF16.
TXT files are supported by all major operating systems, with most platforms including built-in software allowing text files to be opened and edited without any additional software. Text files also form the basis for many other file formats, such as XML, CSV, and more.
