What is Library Of Congress Web Archiving?
Direct Answer: The Library of Congress Web Archive is a bot operated by the United States Library of Congress that manages, preserves, and provides access to archived web content.
The Library of Congress Web Archive uses the Heritrix open-source archival web crawler to collect content from websites at regular intervals. The bot is instructed to bypass robots.txt to obtain a complete representation of websites. It begins with a 'seed URL' and follows links, downloading copies of content to preserve.
User-Agent Identification
The following user-agent strings identify Library Of Congress Web Archiving in your live traffic data:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.97 Safari/537.36 (+https://www.loc.gov/programs/web-archiving/for-site-owners/)
robots.txt Rules for Library Of Congress Web Archiving
Respects robots.txt: No
This bot does not commit to following robots.txt
Library Of Congress Web Archiving does not officially follow robots.txt directives. The only reliable way to control access is through server-side blocking (IP filtering, user-agent rules in your web server config) combined with log monitoring to verify effectiveness.
Need continuous verification across 500+ bots? Can AI See It automates this.
Crawl Behavior
Frequency:Regular Intervals
Request Pattern:Starts With A 'Seed URL' And Follows Links
Official Documentation Quotes
"The Library of Congress (or its agents) collects content from websites at regular intervals, primarily using the Heritrix crawler, which is an open-source archival web crawler."
"Our crawler is instructed to bypass robots.txt in order to obtain the most complete and accurate representation of websites."
Crawl Activity Index
Relative crawl activity for Library Of Congress Web Archiving over the past 28 days. Higher values indicate increased crawling intensity compared to the period baseline.
View recent activity data (last 7 days)
| Date | Activity Index |
|---|---|
| Mar 26, 2026 | 88.0 |
| Mar 27, 2026 | 82.7 |
| Mar 28, 2026 | 83.1 |
| Mar 29, 2026 | 81.8 |
| Mar 30, 2026 | 87.3 |
| Mar 31, 2026 | 90.2 |
| Apr 1, 2026 | 88.9 |
Source: Cloudflare Radar
Why track Library Of Congress Web Archiving traffic?
Identify and classify unknown crawler activity. Library Of Congress Web Archiving may appear in your live traffic data with varying frequency. Tracking its behavior helps you decide whether to allow, throttle, or block it based on actual data.
Protect your crawl budget. Every bot request consumes server resources. Understanding what Library Of Congress Web Archiving crawls helps you prioritize the crawlers that matter.
Log Verification
To verify Library Of Congress Web Archiving traffic in your live traffic data:
- Search access logs for the user-agent strings listed above
- Check if the IP addresses match documented ranges (if provided by United States Library of Congress)
- Verify the crawl pattern matches documented behavior
- Use reverse DNS lookup for additional verification if available
Note: Observed behavior in production environments may differ from official documentation. Live traffic monitoring provides the only reliable verification of actual bot behavior.
Undocumented Information
The following information is not officially documented for Library Of Congress Web Archiving:
- crawl frequency specifics
- IP verification method
Official Documentation
View Official Library Of Congress Web Archiving Documentation →
Information sourced from official documentation. Content generated with AI assistance.