What is Log file analysis?

Log file analysis is the practice of reading a server's raw access logs to see exactly which URLs each crawler fetched, how often, and what status code came back. It is the only fully accurate record of crawler behaviour.

How it works

Every request to your server is logged with a timestamp, the requested URL, the response code, and the user-agent. Filtering those logs by crawler user-agent shows you the ground truth: which pages bots actually reach, which they ignore, and where they hit errors or redirects.

Verification matters because user-agents are trivially spoofed. Real Googlebot and most AI crawlers publish IP ranges you can reverse-check, so you can separate genuine crawler traffic from impostors.

Log file analysis vs the Crawl Stats report

Search Console's Crawl Stats report is a sampled, Google-only summary. Log analysis is unsampled and covers every bot, including GPTBot, PerplexityBot, and Bing. If you want to know whether AI crawlers are reaching a specific page, logs are the only source that can answer it.

Why it matters for B2B

For GEO, logs answer the question that precedes all others: is the AI crawler even fetching this page? Before you tune a page for citations, the logs tell you whether OAI-SearchBot or PerplexityBot has visited it, how recently, and whether it got a clean 200. A page no bot has fetched is invisible regardless of how good it is.

Frequently asked questions

What is log file analysis?

Log file analysis is the practice of reading a server's raw access logs to see exactly which URLs each crawler fetched, how often, and what status code came back; the only fully accurate record of crawler behaviour.

How do you use log file analysis for SEO?

Filter the logs by crawler user-agent to see which pages bots actually reach, spot wasted crawl on low-value URLs, find pages bots never fetch, and catch errors or redirects. Verify user-agents against published IP ranges, since they are easily spoofed.

What tools are used for log file analysis?

Dedicated SEO log analysers such as Screaming Frog's Log File Analyser, or general log-processing pipelines; the key is filtering by verified crawler user-agent rather than the tool itself.

66.249.66.1 - - [07/Jun/2026:10:22:01] "GET /glossary/crawl-budget" 200 "Googlebot"