The ongoing pandemic caused by SARS-CoV-2 emphasizes the importance of molecular surveillance to understand the evolution of the virus and to monitor and plan the epidemiological responses. Prompt analysis, easy visualization and convenient filtering of viral sequences are essential for this purpose. Therefore we have developed CovRadar, a tool for molecular surveillance of the coronavirus spike protein. The spike protein contains the receptor binding domain (RBD) that is used as a target for most vaccine candidates. CovRadar consists of a Snakemake pipeline and a Flask/Dash web application, which combined enable the analysis and visualization of over 2 million sequences in a timely manner. First, CovRadar extracts the regions of interest using local alignment, then builds a codon-aware multiple sequence alignment, infers variants, consensus sequences, phylogenetic trees and finally displays the results in an interactive PDF-like app, making reporting fast, easy and flexible. CovRadar is freely accessible at https://covradar.net, while the code is open-source and available at https://gitlab.com/dacs-hpi/covradar.