File with an .YAML extension contains different types of data stored in the YAML format, readable for a person and independent from any programming language. Data files in this format are usually stored with an .YML extension.

YAML files are used to save and read data in different applications, created in different environments and programming languages supporting YAML libraries, for instance C, C++, C#, Perl, PHP, Python, Ruby, Java. This format is also utilised by the Google application engine.