🤖 Overview

fairad client is a web crawler operated by the ad‑verification and brand‑safety company FairAd (acquired by Integral Ad Science in 2017). Its primary purpose is to programmatically visit web pages to audit the placement, visibility, and context of digital advertisements, feeding data into FairAd’s proprietary brand‑safety and ad‑verification platform. The bot was first documented in public server logs around 2014 and has since been used by advertisers and publishers to ensure ad campaigns are served in appropriate, viewable environments.

🌐 Technical Behavior

The fairad client typically makes HTTP GET requests to a single page per session, then parses the HTML to identify ad tags, iframes, and script‑loaded creatives. It may execute JavaScript to simulate user interactions and measure viewability, employing the same rendering engine as other ad‑verification tools. Requests are sent at a moderate pace—usually 1–5 requests per second per IP—and the bot respects standard HTTP caching headers (Cache‑Control, Expires) to avoid redundant crawling. IP ranges used by FairAd are published in the company’s documentation; they originate from data‑center ASNs such as AS14618 (Amazon AWS) and AS16509 (Amazon) for US‑based scans, with additional ranges in Europe and Asia. The bot uses HTTP/1.1 by default and sends a Via header containing “fairad” for proxy identification.

📋 robots.txt Compliance

According to FairAd’s official guidance (available at https://fair‑ad.com/robots.txt and their help center), the fairad client honors Disallow directives in robots.txt for all user‑agent names that match “fairad”. Publishers can block specific paths by adding “Disallow: /path” under a User‑agent: fairad rule. Multiple publisher reports confirm that the bot stops crawling disallowed sections within minutes of a robots.txt update, making it one of the more compliant ad‑verification crawlers.

🔍 Detection Indicators

The definitive User‑Agent string for this bot is: Mozilla/5.0 (compatible; fairad/1.0; +https://fairad.com/bot.html). Variants include “fairadclient/1.0” and “FairAd‑Bot/1.0”. Behavioral fingerprints include a consistent request ordering—first the page HTML, then image assets in the order they appear in markup—and the absence of common browser headers like Accept‑Language with multiple locales. The bot also sends a custom X‑FairAd‑Bot header set to “true” on all requests, which site operators can use for fine‑grained logging.

📊 Data Usage

Collected data—including ad tag execution logs, viewability measurements, and surrounding page content—is aggregated into FairAd’s reporting dashboard for advertisers and publishers. This data is used exclusively for ad‑quality analytics, brand‑safety scoring, and fraud detection; it is not used to train large language models or build behavioral user profiles. FairAd’s privacy policy (linked from https://fairad.com/privacy) states that raw page content is discarded after processing, retaining only anonymized metrics.

⚙️ Rate Limiting Policy

Although the bot is legitimate, it is rate‑limited because its concurrent scans can tie up server resources during peak traffic or when numerous ad campaigns are being audited simultaneously. A threshold‑based blocking rule (e.g., >50 requests per minute from any IP in the FairAd range) allows site operators to balance verification needs with performance, while still permitting the bot to complete its essential ad‑auditing function.

ⓘ 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.