🤖 Overview

dof-verify is a legitimate web crawler operated by DataOptim (also referred to as DOF), a company specializing in data verification and quality assurance for AI training datasets. First publicly documented in 2022, the bot is designed to periodically fetch web pages to verify the accuracy, freshness, and consistency of content that DataOptim’s customers use to train machine learning models. The crawler feeds data into the company’s proprietary verification platform, which cross‑references scraped content against customer‑provided ground truth labels.

🌐 Technical Behavior

The bot follows a deterministic crawl schedule, issuing requests at a rate of two to five requests per second per IP, according to the official DataOptim documentation published at dataoptim.com/robots. It uses HTTP/1.1 with a persistent connection and sends a User‑Agent string that includes the version number (e.g., dof-verify/2.1). The crawler’s IP ranges are announced via the company’s ASN (AS20789) and are listed in public RDNS records (dof-verify.crawl.dataoptim.com). It respects the Last‑Modified and ETag headers to avoid re‑fetching unchanged content, and it limits concurrent connections to 10 per domain to minimise server load.

📋 robots.txt Compliance

DataOptim explicitly states on their official robots.txt policy page that dof-verify honours all Disallow directives. The bot fetches /robots.txt before each crawl session and caches the file for up to 24 hours. In the rare event of a misconfiguration, documented cases show that the bot will immediately stop crawling a disallowed path upon the next scheduled check. No reported incidents of deliberate violation exist in security advisories.

🔍 Detection Indicators

The primary User‑Agent string is: Mozilla/5.0 (compatible; dof-verify/2.1; +https://dataoptim.com/bot). A secondary header, X‑DOF‑Verify: true, is included in every request to facilitate identification. The bot also appends a From field containing the email address [email protected] in accordance with RFC 9309. Behavioral fingerprints include a consistent request interval of exactly 500‑millisecond gaps and a unique Accept‑Language header of en‑US;q=0.9.

📊 Data Usage

Collected data is used exclusively to verify the correctness of training data for AI models. DataOptim’s platform compares crawled web content against reference snapshots provided by customers, flagging discrepancies such as broken links, stale text, or metadata errors. The verification results are returned to customers via a dashboard and are not used to train any third‑party models. No permanent storage of crawled content occurs; only change logs and validation scores are retained.

⚙️ Rate Limiting Policy

Although dof-verify is not malicious, it is rate‑limited by many webmasters because its bursty request pattern (up to 5 req/s) can momentarily saturate low‑resource servers. A policy of rate limiting or blocking at thresholds (e.g., >100 requests per minute) is recommended to protect application stability without preventing legitimate verification activity.

ⓘ 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.