Crawler (Bot / Spider)
An automated program that browses the web to index content for search engines.
Detailed Explanation
Googlebot is the most famous crawler. It 'visits' pages, follows links, and sends the content back to the search engine's index. 'Crawl Budget' is the number of pages a bot will crawl on your site in a given time; optimizing site speed and internal linking ensures the bot doesn't waste its budget on low-value pages.
Quick Summary
Crawlers (Googlebot, Bingbot, GPTBot, etc.) are programs that download pages, follow links, and feed content into search/AI indexes. They identify via User-Agent headers, respect robots.txt (politely), and operate within a 'crawl budget', the number of pages they'll fetch from your site in a given window.
Key Takeaways
- Googlebot has desktop and mobile variants, mobile is now primary (mobile-first indexing).
- Crawl budget matters for huge sites, bots won't necessarily crawl every page often.
- Faster sites get crawled more, slow servers cause Google to throttle crawl rate.
- Modern Googlebot renders JavaScript (Chromium-based), but rendering is slower than HTML crawling.
- AI crawlers (GPTBot, ClaudeBot, CCBot) can be allowed/blocked separately via robots.txt.
When to use it
- Monitoring crawl stats in Google Search Console to detect indexing issues.
- Blocking AI training bots while keeping search engine bots welcome.
- Optimizing crawl budget for huge e-commerce or media sites.
- Detecting spam crawlers (server logs reveal user-agents).
Common Mistakes
- Blocking Googlebot accidentally (robots.txt typos can deindex an entire site).
- Believing rendering is instant, JS-heavy sites can have indexing delays of days/weeks.
- Serving different content to bots vs users ('cloaking'), Google penalizes this.
- Ignoring crawl errors in Search Console, pile up unnoticed and hurt rankings.
Crawler (Bot / Spider), Frequently Asked
How often does Googlebot crawl my site?
Varies, popular news sites: every few minutes; small sites: every few days/weeks. Check Search Console > Settings > Crawl Stats.
Can I see what Googlebot sees?
Yes, use Search Console's URL Inspection tool, or `curl --user-agent Googlebot https://example.com`.
Should I block AI crawlers?
Depends on your stance. Blocking GPTBot/ClaudeBot/CCBot prevents your content from training models but also from being cited in AI search responses.