Input accept either the nanobody sequence or a PDB format nanobody strucure. If only sequence was provided, the structure will be modeled by NanoNet. The sequence was numbered according to Martin numbering scheme, then CDRs and FRs are seubsequently determined. The intramolecular bonds(and intramolecular bonds with antigen, if input structure contains antigen) are analyzed. Blast analysis will be performed on nanobody sequence against the internal human VH sequence database to determine residues potentially need to be humanized. Final humanized sequence will be determined given the analysis result.