CloudConvert can be used to extract any supported archive type (ZIP, RAR, TAR, TAR.GZ, 7Z and many more).
Therefore use the extract mode parameter, as the following example shows. Please note that the mode parameters needs to be set to extract in both the create process API request and the start process API request (refer to the documentation about the other necassary parameters for starting conversions).
As this mode normally results in multiple output files, it is recommended to use an output storage like S3 or FTP.