ZLib compression is a widely used data compression library and algorithm that's designed to efficiently reduce the size of data.

ZLib data compression is already enabled on all of our Web and Cloud hosting plans. You can double-check this, together with the main information about the ZLib version, on the PHP Info page:

However, the zlib.outputCompression (or zlib.output_compression) PHP option is not enabled by default.

To enable it, open the PHP Configuration → PHP options page, add a checkbox next to zlib.outputCompression, and save the changes:

After this, you'll be able to use ZLib output compression in your projects.