Here we demonstrate the power of combining existing tools to tackle emerging fields such as single-cell proteomics. Packages such as pyteomics, pyOpenMS, Percolator, and Mokapot 27 allowed us to build MS 2 Rescore, a coherent and widely applicable software package for data-driven rescoring. We present MS 2 Rescore not as a static tool, but as an open platform to (1) facilitate the adoption of data-driven rescoring in routine applications, and