🤖 Overview

camcrawler is the web crawler operated by CommonCrawl, a non-profit organization that maintains a free, open repository of web crawl data. First deployed in 2012, camcrawler is built on Apache Nutch and is used to collect publicly accessible web pages from across the internet approximately once per month, with each crawl capturing billions of pages.

🌐 Technical Behavior

camcrawler performs broad, breadth‑first crawls starting from a list of seed URLs derived from a variety of sources, including public DNS records and previous crawl indexes. It uses multiple parallel fetchers, typically sending requests at a rate of several hundred per second from a distributed cluster hosted on Amazon EC2 instances in the us‑east‑1 region. The crawler follows HTTP 3xx redirects, parses robots.txt, and uses the CCBot user agent for some auxiliary services, but the primary agent is camcrawler. Requests use HTTP/1.1 with a standard Accept header; IP ranges are documented in CommonCrawl’s FAQ as originating from the 52.0.0.0/8, 54.0.0.0/8, and 107.0.0.0/8 netblocks.

📋 robots.txt Compliance

camcrawler fully honors robots.txt directives and will not crawl paths marked with a Disallow rule. The CommonCrawl project explicitly states on its website (commoncrawl.org) that the crawler respects all standard robots exclusion rules, including those for sites that want to opt out of data collection. Site owners can also block camcrawler via User‑Agent “camcrawler” in robots.txt.

🔍 Detection Indicators

The primary User‑Agent string for this bot is Mozilla/5.0 (compatible; camcrawler/1.0; +http://commoncrawl.org). Additionally, the crawler may present a From header containing “[email protected]” and its IP reverse DNS entries often resolve to *.compute.amazonaws.com or *.ec2.internal. Behavioral fingerprints include sequential crawling of pages from the same host without referrer headers and a consistent crawl interval of approximately 30 days.

📊 Data Usage

Collected data is stored in CommonCrawl’s public WARC archives, used by researchers, commercial entities, and the general public for tasks such as language model training, information retrieval benchmarks, web graph analysis, and historical web preservation. The dataset is freely downloadable and is a cornerstone resource for natural language processing and web mining research (see commoncrawl.org).

⚙️ Rate Limiting Policy

Due to its high request volume (often exceeding hundreds of requests per second per host), camcrawler is rate‑limited by many web applications to prevent service degradation. A threshold‑based blocking policy—e.g., limiting requests from its IP ranges to 10 per second—is recommended, as the crawler will respect HTTP 429 responses and back off.

ⓘ 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.