Peslyak has been the founder and leader of the Openwall Project since 1999. He is the founder of Openwall, Inc. and has been the CTO since 2003. He served as an advisory board member at the Open Source Computer Emergency Response Team (oCERT) from 2008 until oCERT's conclusion in August 2017.[3] He also co-founded oss-security.[4]
He has spoken at many international conferences, including FOSDEM and CanSecWest. He wrote the foreword to Michał Zalewski's 2005 book Silence on the Wire.[5]