In order for the web content that we produce to reach the widest possible audience, web accessibility should be considered. Furthermore, many institutions are legally required to produce accessible content. aXe is an open-source accessibility auditing library that checks a page against the W3C Web Content Accessibility Guidelines (WCAG) 2.0 and the Section 508 US federal procurement standard. After analyzing a page, the aXe browser extension provides a detailed list of potential issues. For each issue, it lists the problematic snippet of HTML, a description of the potential issue and its severity, and guidelines for fixing the issue. The aXe browser extension is available for Google Chrome and Mozilla Firefox.