SRMAtlas is a database of selected reaction monitoring (SRM) transitions and mass spectra derived from synthetic peptides created for SRM assay development and analyzed on the types of mass spectrometers most frequently used for SRM/MRM experiments— triple quadrupole, Orbitrap, and quadrupole–time-offlight instruments. Users can search SRMAtlas using a protein accession number or peptide sequence, or by uploading a text file containing a list of protein names or peptide sequences Registration not required.