BioEddie is a javascript web browser component which is capable of depicting and editing peptides, oligonucleotides, proteins, antibodies, antibody drug conjugates and nanoparticle conjugates including non-natural or chemically modified residues and other chemical fragments. The tool provides both chemical and biological representation by utilizing sequence-based and chemical structure based definitions . Molecules can be described with full, partial or no chemical structure defined and annotations added to the entire molecule or parts of it.