The FireFox OS Vulnerability Scanner is a BCIT's graduation project which examines the possible integrity and security issues with 3rd party mobile web applications in Firefox OS by scanning for any possible vulnerabilities, APIs permission assignment, and client-side storage security that can be found in these third party applications. This modified scanner is build on an existing program called Watchtower with the integration of new coding and signature files to look for possible instances that would cause DOM based XSS, issues when using client-side storage, and application’s APIs permission assignment in Firefox OS’ web applications. Developers and code reviewers will be able to install this application and scan the web application locally. Once the possible vulnerabilities are located, it will offer recommendations that are related to these possible instances to the user. A HTML report will be saved on the user’s hard drive so the user can retrieve the information later on if they wished to.