https://csp-evaluator.withgoogle.com/

CSP Evaluator allows developers and security experts to check if a Content Security Policy (CSP) serves as a strong mitigation against [cross-site scripting attacks (https://www.google.com/about/appsecurity/learning/xss/). It assists with the process of reviewing CSP policies, which is usually a manual task, and helps identify subtle CSP bypasses which undermine the value of a policy. CSP Evaluator checks are based on a large-scale study (https://research.google.com/pubs/pub45542.html) and are aimed to help developers to harden their CSP and improve the security of their applications. This tool (also available as a Chrome extension) is provided only for the convenience of developers and Google provides no guarantees or warranties for this tool.