File Extensions

.csv

Comma-Separated Values.

.csv

Rows and columns as plain tabular text; used for data import/export, spreadsheets, and databases.

.xlsx

Excel Open XML Spreadsheet.

.xlsx

Structured spreadsheet data stored in a compressed XML package; supports formulas, tables, charts, and multi-sheet data.

.json

JavaScript Object Notation.

.json

Hierarchical key-value pairs in a human-readable text format; semi-structured and used for APIs, configs, and web data exchange.

.txt

Plain Text File.

.txt

Unstructured basic text with no formatting; often used for logs, notes, simple dumps of data.

.jpg

JPEG Image.

.jpg

Compressed image format; unstructured (binary) and used for photos and graphics.

.dat

Generic Data File.

.dat

Raw or proprietary data; structured or unstructured and format varies based on the software that created it.