Ecosystem vs. Library

“How does Tenon differ from X library?” is a question we often get from potential customers. “X Library” in this case is usually one of aXe, the Google Accessibility Developer tools library, HTML Code Sniffer, and the like. This is a sensible question and we’re happy that potential customers are out there doing their research to make an informed decision. We’d like to address them here in this blog post to help make the differences clear. But first, a quick note: We do not comment on the quality of other tools in this post. It is a documented internal policy to not bad-mouth other products. You should always independently assess the quality, accuracy, completeness, or relevance of these products. We offer a free trial for 30 days. We invite you to register and beat on Tenon during that 30 days to see if it is right for you.

Tenon is not just an API

While we’ve been very adamant about our “API first” philosophy, that doesn’t mean we’re “API only” and this is the most important distinction between Tenon and the other products we’re often compared to. Tenon’s goal is to become a singular, holistic toolset for accessibility that can be used by all members of your team. This contrasts the “libraries” pretty significantly and the difference is critical. While a library can add a lot of power to developer tooling, it does nothing for content, QA, or compliance. Tenon’s unique approach starts with the API and builds everything around that.

Web-based system

The web-based interface you interact with on provides the ability to create and edit projects, set up default API settings at both the account & project level, store & retrieve test history, and access high level statistics across the account as a whole or for a specific project. As Tenon grows as a project, more and more features will be added based on customer feedback and demand, allowing the web-based features to support testing and compliance efforts. This includes upcoming features like a Reports API, a Projects API, and a Spider.

API Differences

Tenon’s Test API allows for the testing of either document source or a URL and accepts over a dozen request parameters that allow you to fine-tune what Tenon tests for. Want only WCAG Level A issues? Use the level parameter. Want to test your responsive designs? Pass the appropriate breakpoint value to the viewportwidth parameter. The vast array of test options means there are scores of different ways you can customize how Tenon tests.


Whether you’re looking to put accessibility testing into the hands of developers, content authors, QA analysts, or executives, Tenon is the only tool that provides end-to-end coverage. In fact, Tenon was the first accessibility testing product integrated into Visual Studio, the first into WordPress, the first into Silverstripe, and the first into Drupal. We have Node Modules, Grunt & Gulp plugins, PHP classes, Ruby Gems, and Python wrappers. As a result, Tenon can be integrated quickly into systems like Github, Jira, Jenkins, Protractor, Selenium, and more with minimal effort. All of this means that Tenon is the easiest tool to integrate into existing tools and workflows.

Continued improvement

While the testing rules that exist in the various libraries tend to be quite good, their rate of growth and improvement is sometimes very slow or even stagnant. Tenon’s rate of growth is constant, as demonstrated by our change log.


Nobody matches Tenon’s support. With the various free libraries, you’re likely left with little to no direct support. Some of the free libraries have open issues reported by their users over 2 years ago with no response. Tenon’s users can get live chat support directly from the Tenon team. Even Free Trial users get quick responses to support questions. We are far more responsive to our users than any other accessibility product company, free or paid. If you point out an issue, we will log an issue in our Jira instance and even tell you the Issue ID so you can come back and ask about it later.

Product Direction

We started Tenon in order to revolutionize the way accessibility testing is done. We started with the test API as the backbone, but we haven’t stopped there. Tenon’s features – the ecosystem – continues to grow constantly. We’ve closed almost 1600 Jira tickets, merged in over 220 Pull Requests, created 160 accessibility tests, and continually add new features. As time goes on you can expect more from us in our quest to become the most flexible, robust, and comprehensive web accessibility product on the market.

We invite you to come along for the ride as we fulfill this goal.

Start your free trial of Tenon today!