Compress (ZLIB)
This action compresses the binary using the zlib compression algorithm (using its max compression level for optimum size savings).
When you receive a zlib-compressed message, you must decompress using the Received binary > Uncompress (ZLIB) action, before you try to read the content of the binary message.
Compression is not something you can apply to every message and should use in every scenario; there's plenty of subtleties. Read the Compression tips.
If you're sending a large file, also refer to the Expert: Sending a big file with compression example.