ZMat is a portable mex function to enable zlib/gzip/lzma/lzip/lz4/lz4hc based data compression/decompression and base64 encoding/decoding support in MATLAB and GNU Octave. It is fast and compact, can process a large array within a fraction of a second. Among the 6 supported compression methods, lz4 is the fastest for compression/decompression; lzma is the slowest but has the highest compression ratio; zlib/gzip have the best balance between speed and compression time.