CDR Annotation is an antibody numbering and annotation module used to number the variable region (Fv) of antibody sequences, accurately marking the specific locations of the framework region (Framework Region, FWR) and the complementarity determining region (Complementarity Determining Region, CDR). It supports the IMGT, Kabat, Chothia, Martin, AHo and Wolfguy schemes. When multiple sequences are input at once, you can analyze sequence variations and conservation by viewing the sequence visualization and amino acid frequency plots.