Competing endogenous RNAs or ceRNAs are sets of RNAs including mRNA, transcribed pseudogenes, and long noncoding RNAs that can regulate each other by competing for microRNAs binding. These ceRNAs forms a large-scale regulatory network across the transcriptome, greatly expanding the functional genetic information in the human genome and playing important roles in pathological conditions, such as cancer. TRAceRNA is a computational tool and an online application to assist the exploration of ceRNAs.