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.

HTML5 warning

In Blue HTML5 Client, this action may not work if the external zlib script failed to load.

See Platform notes.