Question

Are System.IO.Compression.GZipStream or System.IO.Compression.Deflate compatible with zlib compression?

Answer 1

From MSDN about System.IO.Compression.GZipStream:

This class represents the gzip data format, which uses an industry standard algorithm for lossless file compression and decompression.

From the zlib FAQ:

The gz* functions in zlib on the other hand use the gzip format.

So zlib and GZipStream should be interoperable, but only if you use the zlib functions for handling the gzip-format.

System.IO.Compression.Deflate and zlib are reportedly not interoperable.

If you need to handle zip files (you probably don’t, but someone else might need this) you need to use SharpZipLib or another third-party library.