The Naval Research Laboratory (NRL) and NRAO worked together to develop a commensal low band system on the NRAO JVLA that takes advantage of the separate optical paths of the low frequency prime focus feeds and the 1-50 GHz Cassegrain feeds. The VLA Low-band Ionosphere and Transient Experiment (VLITE) operates 24/7 recording 64 MHz of bandwidth from the the 330 MHz receivers. We will discuss the development of the real-time DiFX correlator to meet the needs of VLITE as well as lessons learned from commissioning VLITE in the shadow of WIDAR. We also show how a relatively simple commensal system such as VLITE can provide important diagnostics that can be easily missed in the hardware correlator due to limited operation time of the hardware correlator at the VLITE band. Finally we highlight the importance of setting forward looking requirements but also the flexibility for modification of the VLITE software correlator. In particular, the flexibility of the DiFX correlator has led to significant improvements in the overall VLITE system.