There are many products available that allow web designers, developers, and content authors to evaluate the accessibility of their web pages and sites. Many tools also prompt users to make specific repairs. The Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C) maintains an extensive list of such tools in their document Evaluation, Repair, and Transformation Tools for Web Content Accessibility. There are presently dozens of products to choose from, and many of the leading vendors offer multiple products varying considerably in features, functionality, and price. This vast selection leaves web administrators at educational entities with the challenging task of determining which product is the best for supporting their school's web accessibility initiative.

There are a variety of free browser extensions and other tools available that can check accessibility of individual web pages. For a curated and annotated list of tools used by the IT Accessibility Team at the University of Washington, see their Tools and Resources page.

Beyond the free tools, there are many enterprise tools that can crawl an institution's entire website and provide an extensive feature set to help institutions manage their web accessibility efforts. In addition to consulting the list of tools maintained by the WAI, contacting colleagues in your field, and reading product reviews, the following steps are recommended for selecting web accessibility evaluation tools:

  • Review the promotional literature for vendors' products.
  • View online demos of products, if available.
  • Install and test evaluation versions of products, if available.
  • Ask around. Ask vendors for references. Read the archives of discussion lists related to web design or web accessibility.
  • Plan ahead. Know what features you would like in a product, and ask vendors about their support for those features.

Following are examples of questions to consider asking when planning ahead for a purchase of web accessibility tool:

How automatic is an automatic accessibility checker?

Be careful of product marketing literature. Some vendors make bold claims about their numbers of automatic checks. Many aspects of web accessibility evaluation are inherently subjective and require human judgment. Be leery of companies that claim their products will make your website "ADA Compliant".

What rules does the tool check against, and can these be customized?

Most if not all available products are built to check against the W3C's Web Content Accessibility Guidelines (WCAG). However, there are variations in the specific rules they use to measure WCAG conformance. Some companies are more transparent than others in publishing their rules. Knowing how their tools work can be helpful information.  Also, WCAG is an evolving standard, so it's useful to know how quickly the tool can adapt to changes in WCAG, and how much flexibility you have in choosing which rules are applied. For example, the tool may be technically able to check against WCAG 2.1 or higher, but if you're institution's policy requires websites to meet WCAG 2.0, you may want to check only for conformance to this earlier version.

Is the user interface accessible and usable?

As obvious as this question may seem, the answer is not universally "yes." Some products do an excellent job of evaluating web content for accessibility but cannot themselves be operated by users with disabilities.

Are the results easy to understand and act upon?

An accessibility checker is only useful if it provides users with the information and guidance they need to fix their website's accessibility problems. This can best be assessed by inviting a wide variety of individuals from the target user groups to test the product, including people with no prior accessibility knowledge.

Does the tool check site quality issues beyond accessibility?

Sometimes web accessibility is more likely to be embraced by users if it is presented as an issue of web quality, along with other quality issues unrelated to accessibility. Some of the web accessibility products support this approach by including checks for broken links, orphan pages, spelling errors, security issues, search engine optimization, and other web quality issues.

Does the tool check content other than HTML?

Some tools have the ability to perform basic checks of PDFs and other documents, as well as checks to determine whether embedded videos seem to be captioned. The availability of these features may add value to the product, although they should be tested to see if they're reasonable accurate and if the results are meaningful. A inaccurate checker is not better than no checker at all.

Can the tool handle potential obstacles such as passwords and required form fields?

It can be useful to check a website for accessibility on a development server in order to ensure it's fully accessibility prior to going live. Also, it's important to check accessibility of form landing pages.  Most products now have mechanisms for addressing these obstacles, though typically they require manual intervention. Granting the tools access to password-protected content may also raise privacy and security concerns that will need to be addressed during negotiations with the vendor. Be sure to include key stakeholders from your institution in those conversations.