This article introduces the Transitive Consistency Score (TCS) web server; a service making it possible to estimate the local reliability of protein multiple sequence alignments (MSAs) using the TCS index. The evaluation can be used to identify the aligned positions most likely to contain structurally analogous residues and also most likely to support an accurate phylogenetic reconstruction. The TCS scoring scheme has been shown to be accurate predictor of structural alignment correctness among commonly used methods. It has also been shown to outper-form common filtering schemes like Gblocks or tri-mAl when doing MSA post-processing prior to phylo-genetic tree reconstruction. The web server is available from http://tcoffee.crg.cat/tcs.