Andrei Pelinescu-Onciul is the creator of SIP Express Router (SER), the architect behind the core components such as configuration file interpreter, locking synchronization and memory managers, timers, transport layers (UDP, TCP, TLS and SCTP). He is the one that wrote the first line of code (and many more before anyone else got into the project) back in 2001.

During 2005-2008, Kamailio (OpenSER), as a fork of SER, still relied on his code. Starting with version 3.0.0, as a result of SIP Router project, Kamailio and SER share the same core and tm, actually they are built from same source code tree.

Well known for his care about performance and stability, Andrei is today the main developer of, also supervising the contributions to, core and tm module.