For today’s Ask An SEO, we answer the question:
“As an SEO, should I be using log file data, and what can it tell me that tools can’t?”
What Are Log Files
Essentially, log files are the raw record of an interaction with a website. They are reported by the website’s server and typically include information about users and bots, the pages they interact with, and when.
Typically, log files will contain certain information, such as the IP address of the person or bot that interacted with the website, the user agent (i.e., Googlebot, or a browser if it is a human), the time of the interaction, the URL, and the server response code the URL provided.
Example log:
6.249.65.1 - - [19/Feb/2026:14:32:10 +0000] "GET /category/shoes/running-shoes/ HTTP/1.1" 200 15432 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36"
- 6.249.65.1 – This is the IP address of the user agent that hit the website.
- 19/Feb/2026:14:32:10 +0000 – This is the timestamp of the hit.
- GET /category/shoes/running-shoes/ HTTP/1.1 – The HTTP method, the requested URL, and the protocol version.
- 200 – The HTTP status code.
- 15432 – The response size in bytes.
- Mozilla/5.0 (Macintosh; Intel Mac OS X 14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36 – The user agent (i.e., the bot or browser that requested the file)
What Log Files Can Be Used For
Log files are the most accurate recording of how a user or a bot has navigated around your website. They are often considered the most authoritative record of interactions with your website, though CDN caching and infrastructure configuration can affect completeness.
What Search Engines Crawl
One of the most important uses of log files for SEO is to understand what pages on our site search engine bots are crawling.
Log files allow us to see which pages are getting crawled and at what frequency. They can help us validate if important pages are being crawled and whether often-changing pages are being crawled with an increased frequency compared to static pages.
Log files can be used to see if there is crawl waste, i.e., pages that you don’t want to have crawled, or with any real frequency, are taking up crawling time when a bot visits a site. For example, by looking at log files, you may identify that parameterized URLs or paginated pages are getting too much crawl attention compared to your core pages.
This information can be critical in identifying issues with page discovery and crawling.
True Crawl Budget Allocation
Log file analysis can give a true picture of crawl budget. It can help with the identification of which sections of a site are getting the most attention, and which are being neglected by the bots.
This can be critical in seeing if there are poorly linked pages on a site, or if they are being given less crawl priority than those sections of the site with less importance.
Log files can also be helpful after the completion of highly technical SEO work. For example, when a website has been migrated, viewing the log files can aid in identifying how quickly the changes to the site are being discovered.
Through log files, it’s also possible to determine if changes to a website’s structure have actually aided in crawl optimization.
When carrying out SEO experiments, it is necessary to know if a page that is a part of the experiment has been crawled by the bots or not, as this can determine whether the test experience has been seen by them. Log files can give that insight.
Crawl Behavior During Technical Issues
Log files can also be useful in detecting technical issues on a website. For example, there are instances where the status code reported by a crawling tool will not necessarily be the status code that a bot will receive when hitting a page. In that instance, log files would be the only way of identifying that with certainty.
Log files will enable you to see if bots are encountering temporary outages on the site, but also how long it takes them to re-encounter those same pages with the correct status once the issue has been fixed.
Bot Verification
One very helpful feature of log file analysis is in distinguishing between real bots and spoofed bots. This is how you can identify if bots are accessing your site under the guise of being from Google or Microsoft, but are actually from another company. This is important because bots may be getting around your site’s security measures by claiming to be a Googlebot, whereas, in fact, they are looking to carry out nefarious actions on your site, like scraping data.
By using log files, it’s possible to identify the IP range that a bot came from and check it against the known IP ranges of legitimate bots, like Googlebot. This can aid IT teams in providing security for a website without inadvertently blocking genuine search bots that need access to the website for SEO to be effective.
Orphan Pages Discovery
Log files can be used to identify internal pages that tools didn’t detect. For example, Googlebot may know of a page through an external link to it, whereas a crawling tool would only be able to discover it through internal linking or through sitemaps.
Looking through log files can be useful for diagnosing orphan pages on your site that you were simply not aware of. This is also very helpful in identifying legacy URLs that should no longer be accessible via the site but may still be crawled. For example, HTTP URLs or subdomains that have not been migrated properly.
What Other Tools Can’t Tell Us That Log Files Can
If you are currently not using log files, you may well be using other SEO tools to get you partway to the insight that log files can provide.
Analytics Software
Analytics software like Google Analytics can give you an indication of what pages exist on a website, even if bots aren’t necessarily able to access them.
Analytics platforms also give a lot of detail on user behavior across the website. They can give context as to which pages matter most for commercial goals and which are not performing.
They don’t, however, show information about non-user behavior. In fact, most analytics programs are designed to filter out bot behavior to ensure the data provided reflects human users only.
Although they are useful in determining the journey of users, they do not give any indication of the journey of bots. There is no way to determine which sequence of pages a search bot has visited or how often.
Google Search Console/Bing Webmaster Tools
The search engines’ search consoles will often give an overview of the technical health of a website, like crawl issues encountered and when pages were last crawled. However, crawl stats are aggregated and performance data is sampled for large sites. This means you may not be able to get information on specific pages you are interested in.
They also only give information about their bots. This means it can be difficult to bring bot crawl information together, and indeed to see the behavior of bots from companies that do not offer a tool like a search console.
Website Crawlers
Website crawling software can help with mimicking how a search bot might interact with your site, including what it can technically access and what it can’t. However, they do not show you what the bot actually accesses. They can give information on whether, in theory, a page could be crawled by a search bot, but do not give any real-time or historical data on whether the bot has accessed a page, when, or how frequently.
Website crawlers are also mimicking bot behavior in the conditions you are setting them, not necessarily the conditions the search bots are actually encountering. For example, without log files, it is difficult to determine how search bots navigated a site during a DDoS attack or a server outage.
Why You Might Not Use Log Files
There are many reasons why SEOs might not be using log files already.
Difficulty In Obtaining Them
Oftentimes, log files are not straightforward to get to. You may need to speak with your development team. Depending on whether that team is in-house or not, this may literally mean trying to track down who has access to the log files first.
For teams working agency-side, there is an added complexity of companies needing to transfer potentially sensitive information outside of the organization. Log files can include personally identifiable information, for example, IP addresses. For those subject to rules like GDPR, there may be some concern around sending these files to a third party. There may be a need to sanitize the data before sharing it. This can be a material cost of time and resources that a client may not want to spend simply to share their log files with their SEO agency.
User Interface Needs
Once you have access to log files, it isn’t all smooth sailing from there. You will need to understand what you are looking at. Log files in their raw form are simply text files containing string after string of data.
It isn’t something that is easily parsed. To truly make sense of log files, there is usually a need to invest in a program to help decipher them. These can range in price depending on whether they are programs designed to let you run a file through on an ad-hoc basis, or whether you are connecting your log files to them so they stream into the program continuously.
Storage Requirements
There is also a need to store log files. Alongside being secure for the reasons mentioned above, like GDPR, they can be very difficult to store for long periods due to how quickly they grow in size.
For a large ecommerce website, you might see log files reach hundreds of gigabytes over the course of a month. In those instances, it becomes a technical infrastructure issue to store them. Compressing the files can help with this. However, given that issues with search bots can take several months of data to diagnose, or require comparison over long time periods, these files can start to get too big to store cost-effectively.
Perceived Technical Complexity
Once you have your log files in a decipherable format, cleaned and ready to use, you actually need to know what to do with them.
Many SEOs have a big barrier to using log files simply based on the fact they seem too technical to use. They are, after all, just strings of information about hits on the website. This can feel overwhelming.
Should SEOs Use Log Files?
Yes, if you can.
As mentioned above, there are many reasons why you may not be able to get hold of your log files and transform them into a usable data source. However, once you can, it will open up a whole new level of understanding of the technical health of your website and how bots interact with it.
There will be discoveries made that simply could not be achieved without log file data. The tools you are currently using may well get you part of the way there. They will never give you the full picture, however.
More Resources:
- Website Crawling: The What, Why & How To Optimize
- 13 Steps To Boost Your Site’s Crawlability And Indexability
- The Complete Technical SEO Audit Workbook
Featured Image: Paulo Bobita/Search Engine Journal
