Mass Spectrometry has been the gold standard for deciphering information about a protein’s amino acid sequence. However, mass spectrometry is not convenient and accessible to everyday scientists with its large capital equipment expense and advanced expertise requirement. Scientists often need to resort to using core facilities to sequence proteins. Furthermore, mass spectrometry infers amino acids detection by mass:charge ratio, and therefore the approach can be limited because it cannot easily discriminate protein variants, for instance, post-translational modification that do not differ in mass:charge ratio. Quantum-Si’s Platinum™ single-molecule protein sequencer overcomes these challenges with its small footprint, low startup and maintenance costs, and ability to detect changes in amino acid variants even if they have the same mass. In this application note, we demonstrate sequencing and identifying the CDNF, FGF2, and IL6 proteins on Platinum™ in a simple workflow and compare results to mass spectrometry results of the same protein submitted for sequencing to a core facility.