This is a web server to show the behaviour of the Needleman and Wunsch (global) and Smith and Waterman (local) alignment algorithms. Students in this small project are suposed to be able to implement a functional version of both algorithms. The implementation of them is an excellent opportunity to understand the basic mechanisms to perform optimal pairwise alignments. Moreover, the web server can be simply used to explain the dynamic programming paradigm to beginner students in bioinformatics.