For that, the user can provide a PTM position or not, a monoisotopic mass, and a name. I think we will need a drop-down that load that data from unimod (https://www.npmjs.com/package/js-unimod) where all possible modifications are stored. If the user picks one modification, then you query using that modification.
The peptide sequences can be filtered by PTMs, you can search by a pattern expression and also a PTM see documentation here https://spectra-ws.readthedocs.io/en/latest/find_ptm.html
For that, the user can provide a PTM position or not, a monoisotopic mass, and a name. I think we will need a drop-down that load that data from unimod (https://www.npmjs.com/package/js-unimod) where all possible modifications are stored. If the user picks one modification, then you query using that modification.