The library does not require any additional extension loaded in php but it can be optionally paired with the phpiredis (https://github.com/nrk/phpiredis) c-based extension to lower the overhead of serializing and parsing the redis protocol. predis is also available in an asynchronous fashion through the experimental client provided by the predis\async (http://github.com/nrk/predis-async) library.

for a list of frequently asked questions about predis see our faq (https://github.com/nrk/predis/blob/master/faq.md). more details are available on the official wiki (http://wiki.github.com/nrk/predis) of the project.