SCimilarity is a unifying representation of single-cell expression profiles that quantifies similarity between expression states and generalizes to represent new studies without additional training. This enables a novel cell search capability, which sifts through millions of profiles to find cells similar to a query cell state and allows researchers to quickly and systematically leverage massive public scRNA-seq atlases to learn about a cell state of interest. This repository includes snapshots release/prerelease SCimilarity API, documentation, and containerization code.