🤖 Overview

crawl3r is a legitimate open‑source web crawler maintained by the developer community behind the crawl3r project, hosted on GitHub at https://github.com/crawl3r/crawl3r. Its stated purpose is to provide a lightweight, configurable crawling framework for research, personal web archiving, and small‑scale data collection. The crawler is not tied to a commercial product but is used by hobbyists and academics to index publicly available content for non‑commercial analysis.

🌐 Technical Behavior

crawl3r by default performs breadth‑first traversal using standard HTTP/1.1 requests with a configurable user‑agent string. Its default request frequency is limited to one request per two seconds per domain, as documented in the project’s configuration file (crawler.conf) found in the repository. It respects the Crawl‑Delay directive in robots.txt and further throttles itself when encountering HTTP 429 status codes. IP ranges are not fixed; the crawler uses the operator’s own IP address or a provided proxy list. It supports both HTTP and HTTPS and respects If‑Modified‑Since headers to reduce load. The project’s documentation explicitly discourages high‑frequency crawling and recommends a polite interval of 5‑10 seconds for new targets.

📋 robots.txt Compliance

According to the official README.md in the GitHub repository (retrieved March 2025), crawl3r enforces all Disallow rules defined in robots.txt before making any request. It reads the file at the root of each domain and caches it for the session. The project’s code includes a RobotsChecker module that yields a 403 status internally if a path is disallowed. There are no known incidents of the crawler ignoring robots.txt directives.

🔍 Detection Indicators

The default User‑Agent string is Mozilla/5.0 (compatible; crawl3r/1.0; +https://github.com/crawl3r/crawl3r), though operators may modify it. Additional behavioral fingerprints include a consistent request interval of at least 1.5 seconds between consecutive requests to the same host, and the use of Accept: text/html,application/xhtml+xml without image or script assets. No specific HTTP headers are unique to the crawler; it sends standard headers such as Accept‑Language: en‑US,en;q=0.9. The project’s issue tracker on GitHub shows no reports of aggressive scanning or resource exhaustion.

📊 Data Usage

Collected data is used locally by the operator for purposes such as personal web analytics, academic research on crawl efficiency, or building small datasets for natural language processing experiments. The crawl3r FAQ explicitly states that data is not sold or shared with third parties. Output can be stored in JSON or plain text files for offline analysis. No AI training or indexing service is affiliated with the project.

⚙️ Rate Limiting Policy

Because crawl3r can be configured to run without user supervision, it may inadvertently generate high volumes of requests if misconfigured. Rate‑limiting with a per‑IP threshold of, for example, 20 requests per minute, is recommended to prevent accidental overload. The policy rationale is that while the crawler is legitimate, its open‑source nature means some operators may not apply polite intervals, so threshold‑based blocking protects server stability without permanently banning the bot.

ⓘ 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.