WAVE, developed by WebAIM at Utah State University, is the most widely used free web accessibility evaluation tool. You enter a URL or use the browser extension, and WAVE annotates the live page with icons showing exactly where accessibility errors, alerts, and best practice issues are located. The visual, in-context presentation makes it significantly easier to understand where problems exist than a plain list of error codes.
Accessibility matters for SEO as well as compliance. Screen-reader-friendly content with proper heading structure, descriptive alt text, and good contrast ratios is also better content for search engines. Many of the factors that make a page accessible overlap with factors that make it easier to crawl and understand: clear document structure, descriptive labels, and logical reading order. Running WAVE on your key pages surfaces improvements that benefit both disabled users and search performance.
The errors WAVE identifies include missing alt text, empty links, missing form labels, and insufficient colour contrast, all of which represent real barriers for users with disabilities. The alerts section highlights potential issues worth reviewing, and the structural view shows you how assistive technologies will interpret your page hierarchy. I find WAVE particularly useful during development and pre-launch audits: catching accessibility issues before going live is much cheaper than fixing them after the fact. The free web version is straightforward to use and requires no account. For ongoing accessibility monitoring across an entire site, you’ll want to look at more comprehensive tools, but for page-level spot-checking WAVE is excellent.