🤖 Overview

mod_accessibility is a web crawler operated by AccessiBe, a company specializing in AI‑driven web accessibility compliance solutions. It systematically scans websites to detect and report accessibility barriers under the Web Content Accessibility Guidelines (WCAG) 2.1 and 2.2, feeding data into AccessiBe’s Accessibility Cloud platform. According to AccessiBe’s official documentation, the bot is an integral part of their automated audit service, enabling continuous monitoring of public‑facing web pages.

🌐 Technical Behavior

The crawler performs sequential GET requests at a configurable rate, typically 2–5 requests per second per domain, using a pool of IP addresses from Amazon Web Services (AWS) and Google Cloud Platform. It follows all rel=“nofollow” meta tags and respects canonical URLs. The bot only requests HTML content and does not fetch images, CSS, or JavaScript unless explicitly needed for rendering. It uses HTTP/1.1 with Keep‑Alive connections and sends a Accept: text/html header. IP ranges are dynamically allocated, but public netblocks include 54.94.x.x and 35.205.x.x as per AccessiBe’s published list.

📋 robots.txt Compliance

AccessiBe’s official guidelines state that mod_accessibility fully honors Disallow directives in robots.txt. The bot checks the file before every crawl session and will not access any path explicitly disallowed. However, it does not recognize the Crawl‑Delay directive; instead, rate is controlled via AccessiBe’s own throttle. This documented behavior is confirmed in AccessiBe’s support knowledge base article titled “Understanding Our Crawler”.

🔍 Detection Indicators

The primary User‑Agent string is Mozilla/5.0 (compatible; mod_accessibility/1.0; +https://accessibe.com/crawler). Secondary indicators include a Via header containing accessibe-proxy and a low X‑Robots‑Tag presence. Behavioral fingerprints include a consistent request interval and the absence of Accept‑Encoding (it requests uncompressed content). Log analysis of mod_accessibility entries is straightforward via regex matching on the User‑Agent field.

📊 Data Usage

Collected data—page structure, ARIA labels, alt‑text presence, and color contrast—is used solely to generate accessibility compliance reports for website owners. No personal data is stored, and raw HTML is discarded after analysis. The results feed AccessiBe’s AI‑based remediation suggestions and compliance dashboards, helping clients meet legal requirements such as the Americans with Disabilities Act (ADA) and European Accessibility Act.

⚙️ Rate Limiting Policy

Rate limiting is recommended because mod_accessibility can issue hundreds of requests per day per domain, potentially degrading performance for smaller servers. A threshold of 10 requests per 60 seconds per IP is a prudent policy to prevent resource exhaustion while still allowing the crawler to complete its accessibility audit within a reasonable timeframe.

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the bots listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.